(function () {
  'use strict';

  /**
   * Utility module to work with key-value stores.
   *
   * @module map
   */

  /**
   * Creates a new Map instance.
   *
   * @function
   * @return {Map<any, any>}
   *
   * @function
   */
  const create$6 = () => new Map();

  /**
   * Copy a Map object into a fresh Map object.
   *
   * @function
   * @template X,Y
   * @param {Map<X,Y>} m
   * @return {Map<X,Y>}
   */
  const copy = m => {
    const r = create$6();
    m.forEach((v, k) => { r.set(k, v); });
    return r
  };

  /**
   * Get map property. Create T if property is undefined and set T on map.
   *
   * ```js
   * const listeners = map.setIfUndefined(events, 'eventName', set.create)
   * listeners.add(listener)
   * ```
   *
   * @function
   * @template V,K
   * @template {Map<K,V>} MAP
   * @param {MAP} map
   * @param {K} key
   * @param {function():V} createT
   * @return {V}
   */
  const setIfUndefined = (map, key, createT) => {
    let set = map.get(key);
    if (set === undefined) {
      map.set(key, set = createT());
    }
    return set
  };

  /**
   * Creates an Array and populates it with the content of all key-value pairs using the `f(value, key)` function.
   *
   * @function
   * @template K
   * @template V
   * @template R
   * @param {Map<K,V>} m
   * @param {function(V,K):R} f
   * @return {Array<R>}
   */
  const map$1 = (m, f) => {
    const res = [];
    for (const [key, value] of m) {
      res.push(f(value, key));
    }
    return res
  };

  /**
   * Tests whether any key-value pairs pass the test implemented by `f(value, key)`.
   *
   * @todo should rename to some - similarly to Array.some
   *
   * @function
   * @template K
   * @template V
   * @param {Map<K,V>} m
   * @param {function(V,K):boolean} f
   * @return {boolean}
   */
  const any = (m, f) => {
    for (const [key, value] of m) {
      if (f(value, key)) {
        return true
      }
    }
    return false
  };

  /**
   * Utility module to work with sets.
   *
   * @module set
   */

  const create$5 = () => new Set();

  /**
   * Utility module to work with Arrays.
   *
   * @module array
   */


  /**
   * Return the last element of an array. The element must exist
   *
   * @template L
   * @param {ArrayLike<L>} arr
   * @return {L}
   */
  const last = arr => arr[arr.length - 1];

  /**
   * Transforms something array-like to an actual Array.
   *
   * @function
   * @template T
   * @param {ArrayLike<T>|Iterable<T>} arraylike
   * @return {T}
   */
  const from = Array.from;

  const isArray = Array.isArray;

  /**
   * @param {string} s
   * @return {string}
   */
  const toLowerCase = s => s.toLowerCase();

  const trimLeftRegex = /^\s*/g;

  /**
   * @param {string} s
   * @return {string}
   */
  const trimLeft = s => s.replace(trimLeftRegex, '');

  const fromCamelCaseRegex = /([A-Z])/g;

  /**
   * @param {string} s
   * @param {string} separator
   * @return {string}
   */
  const fromCamelCase = (s, separator) => trimLeft(s.replace(fromCamelCaseRegex, match => `${separator}${toLowerCase(match)}`));

  /**
   * @param {string} str
   * @return {Uint8Array}
   */
  const _encodeUtf8Polyfill = str => {
    const encodedString = unescape(encodeURIComponent(str));
    const len = encodedString.length;
    const buf = new Uint8Array(len);
    for (let i = 0; i < len; i++) {
      buf[i] = /** @type {number} */ (encodedString.codePointAt(i));
    }
    return buf
  };

  /* c8 ignore next */
  const utf8TextEncoder = /** @type {TextEncoder} */ (typeof TextEncoder !== 'undefined' ? new TextEncoder() : null);

  /**
   * @param {string} str
   * @return {Uint8Array}
   */
  const _encodeUtf8Native = str => utf8TextEncoder.encode(str);

  /**
   * @param {string} str
   * @return {Uint8Array}
   */
  /* c8 ignore next */
  const encodeUtf8 = utf8TextEncoder ? _encodeUtf8Native : _encodeUtf8Polyfill;

  /* c8 ignore next */
  let utf8TextDecoder = typeof TextDecoder === 'undefined' ? null : new TextDecoder('utf-8', { fatal: true, ignoreBOM: true });

  /* c8 ignore start */
  if (utf8TextDecoder && utf8TextDecoder.decode(new Uint8Array()).length === 1) {
    // Safari doesn't handle BOM correctly.
    // This fixes a bug in Safari 13.0.5 where it produces a BOM the first time it is called.
    // utf8TextDecoder.decode(new Uint8Array()).length === 1 on the first call and
    // utf8TextDecoder.decode(new Uint8Array()).length === 1 on the second call
    // Another issue is that from then on no BOM chars are recognized anymore
    /* c8 ignore next */
    utf8TextDecoder = null;
  }

  /**
   * Often used conditions.
   *
   * @module conditions
   */

  /**
   * @template T
   * @param {T|null|undefined} v
   * @return {T|null}
   */
  /* c8 ignore next */
  const undefinedToNull = v => v === undefined ? null : v;

  /* eslint-env browser */

  /**
   * Isomorphic variable storage.
   *
   * Uses LocalStorage in the browser and falls back to in-memory storage.
   *
   * @module storage
   */

  /* c8 ignore start */
  class VarStoragePolyfill {
    constructor () {
      this.map = new Map();
    }

    /**
     * @param {string} key
     * @param {any} newValue
     */
    setItem (key, newValue) {
      this.map.set(key, newValue);
    }

    /**
     * @param {string} key
     */
    getItem (key) {
      return this.map.get(key)
    }
  }
  /* c8 ignore stop */

  /**
   * @type {any}
   */
  let _localStorage = new VarStoragePolyfill();
  let usePolyfill = true;

  /* c8 ignore start */
  try {
    // if the same-origin rule is violated, accessing localStorage might thrown an error
    if (typeof localStorage !== 'undefined') {
      _localStorage = localStorage;
      usePolyfill = false;
    }
  } catch (e) { }
  /* c8 ignore stop */

  /**
   * This is basically localStorage in browser, or a polyfill in nodejs
   */
  /* c8 ignore next */
  const varStorage = _localStorage;

  /**
   * Utility functions for working with EcmaScript objects.
   *
   * @module object
   */


  /**
   * Object.assign
   */
  const assign = Object.assign;

  /**
   * @param {Object<string,any>} obj
   */
  const keys = Object.keys;

  /**
   * @template V
   * @param {{[k:string]:V}} obj
   * @param {function(V,string):any} f
   */
  const forEach$1 = (obj, f) => {
    for (const key in obj) {
      f(obj[key], key);
    }
  };

  /**
   * @todo implement mapToArray & map
   *
   * @template R
   * @param {Object<string,any>} obj
   * @param {function(any,string):R} f
   * @return {Array<R>}
   */
  const map = (obj, f) => {
    const results = [];
    for (const key in obj) {
      results.push(f(obj[key], key));
    }
    return results
  };

  /**
   * @param {Object<string,any>} obj
   * @return {number}
   */
  const length$1 = obj => keys(obj).length;

  /**
   * @param {Object|undefined} obj
   */
  const isEmpty = obj => {
    // eslint-disable-next-line
    for (const _k in obj) {
      return false
    }
    return true
  };

  /**
   * @param {Object<string,any>} obj
   * @param {function(any,string):boolean} f
   * @return {boolean}
   */
  const every = (obj, f) => {
    for (const key in obj) {
      if (!f(obj[key], key)) {
        return false
      }
    }
    return true
  };

  /**
   * Calls `Object.prototype.hasOwnProperty`.
   *
   * @param {any} obj
   * @param {string|symbol} key
   * @return {boolean}
   */
  const hasProperty = (obj, key) => Object.prototype.hasOwnProperty.call(obj, key);

  /**
   * @param {Object<string,any>} a
   * @param {Object<string,any>} b
   * @return {boolean}
   */
  const equalFlat = (a, b) => a === b || (length$1(a) === length$1(b) && every(a, (val, key) => (val !== undefined || hasProperty(b, key)) && b[key] === val));

  /**
   * Common functions and function call helpers.
   *
   * @module function
   */


  /**
   * Calls all functions in `fs` with args. Only throws after all functions were called.
   *
   * @param {Array<function>} fs
   * @param {Array<any>} args
   */
  const callAll = (fs, args, i = 0) => {
    try {
      for (; i < fs.length; i++) {
        fs[i](...args);
      }
    } finally {
      if (i < fs.length) {
        callAll(fs, args, i + 1);
      }
    }
  };

  /**
   * @template T
   *
   * @param {T} a
   * @param {T} b
   * @return {boolean}
   */
  const equalityStrict = (a, b) => a === b;

  /* c8 ignore start */

  /**
   * @param {any} a
   * @param {any} b
   * @return {boolean}
   */
  const equalityDeep = (a, b) => {
    if (a == null || b == null) {
      return equalityStrict(a, b)
    }
    if (a.constructor !== b.constructor) {
      return false
    }
    if (a === b) {
      return true
    }
    switch (a.constructor) {
      case ArrayBuffer:
        a = new Uint8Array(a);
        b = new Uint8Array(b);
      // eslint-disable-next-line no-fallthrough
      case Uint8Array: {
        if (a.byteLength !== b.byteLength) {
          return false
        }
        for (let i = 0; i < a.length; i++) {
          if (a[i] !== b[i]) {
            return false
          }
        }
        break
      }
      case Set: {
        if (a.size !== b.size) {
          return false
        }
        for (const value of a) {
          if (!b.has(value)) {
            return false
          }
        }
        break
      }
      case Map: {
        if (a.size !== b.size) {
          return false
        }
        for (const key of a.keys()) {
          if (!b.has(key) || !equalityDeep(a.get(key), b.get(key))) {
            return false
          }
        }
        break
      }
      case Object:
        if (length$1(a) !== length$1(b)) {
          return false
        }
        for (const key in a) {
          if (!hasProperty(a, key) || !equalityDeep(a[key], b[key])) {
            return false
          }
        }
        break
      case Array:
        if (a.length !== b.length) {
          return false
        }
        for (let i = 0; i < a.length; i++) {
          if (!equalityDeep(a[i], b[i])) {
            return false
          }
        }
        break
      default:
        return false
    }
    return true
  };

  /**
   * @template V
   * @template {V} OPTS
   *
   * @param {V} value
   * @param {Array<OPTS>} options
   */
  // @ts-ignore
  const isOneOf = (value, options) => options.includes(value);

  /**
   * Isomorphic module to work access the environment (query params, env variables).
   *
   * @module map
   */


  /* c8 ignore next */
  // @ts-ignore
  const isNode = typeof process !== 'undefined' && process.release &&
    /node|io\.js/.test(process.release.name);
  /* c8 ignore next */
  const isBrowser = typeof window !== 'undefined' && typeof document !== 'undefined' && !isNode;

  /**
   * @type {Map<string,string>}
   */
  let params;

  /* c8 ignore start */
  const computeParams = () => {
    if (params === undefined) {
      if (isNode) {
        params = create$6();
        const pargs = process.argv;
        let currParamName = null;
        for (let i = 0; i < pargs.length; i++) {
          const parg = pargs[i];
          if (parg[0] === '-') {
            if (currParamName !== null) {
              params.set(currParamName, '');
            }
            currParamName = parg;
          } else {
            if (currParamName !== null) {
              params.set(currParamName, parg);
              currParamName = null;
            }
          }
        }
        if (currParamName !== null) {
          params.set(currParamName, '');
        }
        // in ReactNative for example this would not be true (unless connected to the Remote Debugger)
      } else if (typeof location === 'object') {
        params = create$6(); // eslint-disable-next-line no-undef
        (location.search || '?').slice(1).split('&').forEach((kv) => {
          if (kv.length !== 0) {
            const [key, value] = kv.split('=');
            params.set(`--${fromCamelCase(key, '-')}`, value);
            params.set(`-${fromCamelCase(key, '-')}`, value);
          }
        });
      } else {
        params = create$6();
      }
    }
    return params
  };
  /* c8 ignore stop */

  /**
   * @param {string} name
   * @return {boolean}
   */
  /* c8 ignore next */
  const hasParam = (name) => computeParams().has(name);

  /**
   * @param {string} name
   * @param {string} defaultVal
   * @return {string}
   */
  /* c8 ignore next 2 */
  const getParam = (name, defaultVal) =>
    computeParams().get(name) || defaultVal;

  /**
   * @param {string} name
   * @return {string|null}
   */
  /* c8 ignore next 4 */
  const getVariable = (name) =>
    isNode
      ? undefinedToNull(process.env[name.toUpperCase()])
      : undefinedToNull(varStorage.getItem(name));

  /**
   * @param {string} name
   * @return {boolean}
   */
  /* c8 ignore next 2 */
  const hasConf = (name) =>
    hasParam('--' + name) || getVariable(name) !== null;

  /* c8 ignore next */
  hasConf('production');

  /* c8 ignore next 2 */
  const forceColor = isNode &&
    isOneOf(process.env.FORCE_COLOR, ['true', '1', '2']);

  /* c8 ignore start */
  const supportsColor = !hasParam('no-colors') &&
    (!isNode || process.stdout.isTTY || forceColor) && (
    !isNode || hasParam('color') || forceColor ||
      getVariable('COLORTERM') !== null ||
      (getVariable('TERM') || '').includes('color')
  );
  /* c8 ignore stop */

  /**
   * Working with value pairs.
   *
   * @module pair
   */

  /**
   * @template L,R
   */
  class Pair {
    /**
     * @param {L} left
     * @param {R} right
     */
    constructor (left, right) {
      this.left = left;
      this.right = right;
    }
  }

  /**
   * @template L,R
   * @param {L} left
   * @param {R} right
   * @return {Pair<L,R>}
   */
  const create$4 = (left, right) => new Pair(left, right);

  /**
   * @template L,R
   * @param {Array<Pair<L,R>>} arr
   * @param {function(L, R):any} f
   */
  const forEach = (arr, f) => arr.forEach(p => f(p.left, p.right));

  /* eslint-env browser */


  /* c8 ignore start */
  /**
   * @type {Document}
   */
  const doc = /** @type {Document} */ (typeof document !== 'undefined' ? document : {});

  /**
   * @param {string} name
   * @return {HTMLElement}
   */
  const createElement = name => doc.createElement(name);

  /**
   * @return {DocumentFragment}
   */
  const createDocumentFragment = () => doc.createDocumentFragment();

  /**
   * @param {string} text
   * @return {Text}
   */
  const createTextNode = text => doc.createTextNode(text);

  /** @type {DOMParser} */ (typeof DOMParser !== 'undefined' ? new DOMParser() : null);

  /**
   * @param {Element} el
   * @param {Array<pair.Pair<string,string|boolean>>} attrs Array of key-value pairs
   * @return {Element}
   */
  const setAttributes = (el, attrs) => {
    forEach(attrs, (key, value) => {
      if (value === false) {
        el.removeAttribute(key);
      } else if (value === true) {
        el.setAttribute(key, '');
      } else {
        // @ts-ignore
        el.setAttribute(key, value);
      }
    });
    return el
  };

  /**
   * @param {Array<Node>|HTMLCollection} children
   * @return {DocumentFragment}
   */
  const fragment = children => {
    const fragment = createDocumentFragment();
    for (let i = 0; i < children.length; i++) {
      appendChild(fragment, children[i]);
    }
    return fragment
  };

  /**
   * @param {Element} parent
   * @param {Array<Node>} nodes
   * @return {Element}
   */
  const append = (parent, nodes) => {
    appendChild(parent, fragment(nodes));
    return parent
  };

  /**
   * @param {EventTarget} el
   * @param {string} name
   * @param {EventListener} f
   */
  const addEventListener = (el, name, f) => el.addEventListener(name, f);

  /**
   * @param {string} name
   * @param {Array<pair.Pair<string,string>|pair.Pair<string,boolean>>} attrs Array of key-value pairs
   * @param {Array<Node>} children
   * @return {Element}
   */
  const element = (name, attrs = [], children = []) =>
    append(setAttributes(createElement(name), attrs), children);

  /**
   * @param {string} t
   * @return {Text}
   */
  const text = createTextNode;

  /**
   * @param {Map<string,string>} m
   * @return {string}
   */
  const mapToStyleString = m => map$1(m, (value, key) => `${key}:${value};`).join('');

  /**
   * @param {Node} parent
   * @param {Node} child
   * @return {Node}
   */
  const appendChild = (parent, child) => parent.appendChild(child);

  doc.ELEMENT_NODE;
  doc.TEXT_NODE;
  doc.CDATA_SECTION_NODE;
  doc.COMMENT_NODE;
  doc.DOCUMENT_NODE;
  doc.DOCUMENT_TYPE_NODE;
  doc.DOCUMENT_FRAGMENT_NODE;
  /* c8 ignore stop */

  /**
   * JSON utility functions.
   *
   * @module json
   */

  /**
   * Transform JavaScript object to JSON.
   *
   * @param {any} object
   * @return {string}
   */
  const stringify = JSON.stringify;

  /* global requestIdleCallback, requestAnimationFrame, cancelIdleCallback, cancelAnimationFrame */

  /**
   * Utility module to work with EcmaScript's event loop.
   *
   * @module eventloop
   */

  /**
   * @type {Array<function>}
   */
  let queue = [];

  const _runQueue = () => {
    for (let i = 0; i < queue.length; i++) {
      queue[i]();
    }
    queue = [];
  };

  /**
   * @param {function():void} f
   */
  const enqueue = f => {
    queue.push(f);
    if (queue.length === 1) {
      setTimeout(_runQueue, 0);
    }
  };

  /**
   * Common Math expressions.
   *
   * @module math
   */

  const floor = Math.floor;
  const ceil = Math.ceil;
  const abs = Math.abs;
  const round = Math.round;
  const log10 = Math.log10;

  /**
   * @function
   * @param {number} a
   * @param {number} b
   * @return {number} The sum of a and b
   */
  const add = (a, b) => a + b;

  /**
   * @function
   * @param {number} a
   * @param {number} b
   * @return {number} The smaller element of a and b
   */
  const min = (a, b) => a < b ? a : b;

  /**
   * @function
   * @param {number} a
   * @param {number} b
   * @return {number} The bigger element of a and b
   */
  const max = (a, b) => a > b ? a : b;
  /**
   * Base 10 exponential function. Returns the value of 10 raised to the power of pow.
   *
   * @param {number} exp
   * @return {number}
   */
  const exp10 = exp => Math.pow(10, exp);

  /**
   * @param {number} n
   * @return {boolean} Wether n is negative. This function also differentiates between -0 and +0
   */
  const isNegativeZero = n => n !== 0 ? n < 0 : 1 / n < 0;

  /**
   * Utility module to work with EcmaScript Symbols.
   *
   * @module symbol
   */

  /**
   * Return fresh symbol.
   *
   * @return {Symbol}
   */
  const create$3 = Symbol;

  /**
   * Utility module to convert metric values.
   *
   * @module metric
   */


  const prefixUp = ['', 'k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'];
  const prefixDown = ['', 'm', 'μ', 'n', 'p', 'f', 'a', 'z', 'y'];

  /**
   * Calculate the metric prefix for a number. Assumes E.g. `prefix(1000) = { n: 1, prefix: 'k' }`
   *
   * @param {number} n
   * @param {number} [baseMultiplier] Multiplier of the base (10^(3*baseMultiplier)). E.g. `convert(time, -3)` if time is already in milli seconds
   * @return {{n:number,prefix:string}}
   */
  const prefix = (n, baseMultiplier = 0) => {
    const nPow = n === 0 ? 0 : log10(n);
    let mult = 0;
    while (nPow < mult * 3 && baseMultiplier > -8) {
      baseMultiplier--;
      mult--;
    }
    while (nPow >= 3 + mult * 3 && baseMultiplier < 8) {
      baseMultiplier++;
      mult++;
    }
    const prefix = baseMultiplier < 0 ? prefixDown[-baseMultiplier] : prefixUp[baseMultiplier];
    return {
      n: round((mult > 0 ? n / exp10(mult * 3) : n * exp10(mult * -3)) * 1e12) / 1e12,
      prefix
    }
  };

  /**
   * Utility module to work with time.
   *
   * @module time
   */


  /**
   * Return current unix time.
   *
   * @return {number}
   */
  const getUnixTime = Date.now;

  /**
   * Transform time (in ms) to a human readable format. E.g. 1100 => 1.1s. 60s => 1min. .001 => 10μs.
   *
   * @param {number} d duration in milliseconds
   * @return {string} humanized approximation of time
   */
  const humanizeDuration = d => {
    if (d < 60000) {
      const p = prefix(d, -1);
      return round(p.n * 100) / 100 + p.prefix + 's'
    }
    d = floor(d / 1000);
    const seconds = d % 60;
    const minutes = floor(d / 60) % 60;
    const hours = floor(d / 3600) % 24;
    const days = floor(d / 86400);
    if (days > 0) {
      return days + 'd' + ((hours > 0 || minutes > 30) ? ' ' + (minutes > 30 ? hours + 1 : hours) + 'h' : '')
    }
    if (hours > 0) {
      /* c8 ignore next */
      return hours + 'h' + ((minutes > 0 || seconds > 30) ? ' ' + (seconds > 30 ? minutes + 1 : minutes) + 'min' : '')
    }
    return minutes + 'min' + (seconds > 0 ? ' ' + seconds + 's' : '')
  };

  const BOLD = create$3();
  const UNBOLD = create$3();
  const BLUE = create$3();
  const GREY = create$3();
  const GREEN = create$3();
  const RED = create$3();
  const PURPLE = create$3();
  const ORANGE = create$3();
  const UNCOLOR = create$3();

  /* c8 ignore start */
  /**
   * @param {Array<string|Symbol|Object|number>} args
   * @return {Array<string|object|number>}
   */
  const computeNoColorLoggingArgs = args => {
    const logArgs = [];
    // try with formatting until we find something unsupported
    let i = 0;
    for (; i < args.length; i++) {
      const arg = args[i];
      if (arg.constructor === String || arg.constructor === Number) ; else if (arg.constructor === Object) {
        logArgs.push(JSON.stringify(arg));
      }
    }
    return logArgs
  };
  /* c8 ignore stop */

  /**
   * Isomorphic logging module with support for colors!
   *
   * @module logging
   */


  /**
   * @type {Object<Symbol,pair.Pair<string,string>>}
   */
  const _browserStyleMap = {
    [BOLD]: create$4('font-weight', 'bold'),
    [UNBOLD]: create$4('font-weight', 'normal'),
    [BLUE]: create$4('color', 'blue'),
    [GREEN]: create$4('color', 'green'),
    [GREY]: create$4('color', 'grey'),
    [RED]: create$4('color', 'red'),
    [PURPLE]: create$4('color', 'purple'),
    [ORANGE]: create$4('color', 'orange'), // not well supported in chrome when debugging node with inspector - TODO: deprecate
    [UNCOLOR]: create$4('color', 'black')
  };

  /**
   * @param {Array<string|Symbol|Object|number>} args
   * @return {Array<string|object|number>}
   */
  /* c8 ignore start */
  const computeBrowserLoggingArgs = (args) => {
    const strBuilder = [];
    const styles = [];
    const currentStyle = create$6();
    /**
     * @type {Array<string|Object|number>}
     */
    let logArgs = [];
    // try with formatting until we find something unsupported
    let i = 0;
    for (; i < args.length; i++) {
      const arg = args[i];
      // @ts-ignore
      const style = _browserStyleMap[arg];
      if (style !== undefined) {
        currentStyle.set(style.left, style.right);
      } else {
        if (arg.constructor === String || arg.constructor === Number) {
          const style = mapToStyleString(currentStyle);
          if (i > 0 || style.length > 0) {
            strBuilder.push('%c' + arg);
            styles.push(style);
          } else {
            strBuilder.push(arg);
          }
        } else {
          break
        }
      }
    }
    if (i > 0) {
      // create logArgs with what we have so far
      logArgs = styles;
      logArgs.unshift(strBuilder.join(''));
    }
    // append the rest
    for (; i < args.length; i++) {
      const arg = args[i];
      if (!(arg instanceof Symbol)) {
        logArgs.push(arg);
      }
    }
    return logArgs
  };
  /* c8 ignore stop */

  /* c8 ignore start */
  const computeLoggingArgs = supportsColor
    ? computeBrowserLoggingArgs
    : computeNoColorLoggingArgs;
  /* c8 ignore stop */

  /**
   * @param {Array<string|Symbol|Object|number>} args
   */
  const print = (...args) => {
    console.log(...computeLoggingArgs(args));
    /* c8 ignore next */
    vconsoles.forEach((vc) => vc.print(args));
  };
  /* c8 ignore stop */

  /**
   * @param {Error} err
   */
  /* c8 ignore start */
  const printError = (err) => {
    console.error(err);
    vconsoles.forEach((vc) => vc.printError(err));
  };
  /* c8 ignore stop */

  /**
   * @param {string} url image location
   * @param {number} height height of the image in pixel
   */
  /* c8 ignore start */
  const printImg = (url, height) => {
    if (isBrowser) {
      console.log(
        '%c                      ',
        `font-size: ${height}px; background-size: contain; background-repeat: no-repeat; background-image: url(${url})`
      );
      // console.log('%c                ', `font-size: ${height}x; background: url(${url}) no-repeat;`)
    }
    vconsoles.forEach((vc) => vc.printImg(url, height));
  };
  /* c8 ignore stop */

  /**
   * @param {string} base64
   * @param {number} height
   */
  /* c8 ignore next 2 */
  const printImgBase64 = (base64, height) =>
    printImg(`data:image/gif;base64,${base64}`, height);

  /**
   * @param {Array<string|Symbol|Object|number>} args
   */
  const group = (...args) => {
    console.group(...computeLoggingArgs(args));
    /* c8 ignore next */
    vconsoles.forEach((vc) => vc.group(args));
  };

  /**
   * @param {Array<string|Symbol|Object|number>} args
   */
  const groupCollapsed = (...args) => {
    console.groupCollapsed(...computeLoggingArgs(args));
    /* c8 ignore next */
    vconsoles.forEach((vc) => vc.groupCollapsed(args));
  };

  const groupEnd = () => {
    console.groupEnd();
    /* c8 ignore next */
    vconsoles.forEach((vc) => vc.groupEnd());
  };

  const vconsoles = create$5();

  /**
   * @param {Array<string|Symbol|Object|number>} args
   * @return {Array<Element>}
   */
  /* c8 ignore start */
  const _computeLineSpans = (args) => {
    const spans = [];
    const currentStyle = new Map();
    // try with formatting until we find something unsupported
    let i = 0;
    for (; i < args.length; i++) {
      const arg = args[i];
      // @ts-ignore
      const style = _browserStyleMap[arg];
      if (style !== undefined) {
        currentStyle.set(style.left, style.right);
      } else {
        if (arg.constructor === String || arg.constructor === Number) {
          // @ts-ignore
          const span = element('span', [
            create$4('style', mapToStyleString(currentStyle))
          ], [text(arg.toString())]);
          if (span.innerHTML === '') {
            span.innerHTML = '&nbsp;';
          }
          spans.push(span);
        } else {
          break
        }
      }
    }
    // append the rest
    for (; i < args.length; i++) {
      let content = args[i];
      if (!(content instanceof Symbol)) {
        if (content.constructor !== String && content.constructor !== Number) {
          content = ' ' + stringify(content) + ' ';
        }
        spans.push(
          element('span', [], [text(/** @type {string} */ (content))])
        );
      }
    }
    return spans
  };
  /* c8 ignore stop */

  const lineStyle =
    'font-family:monospace;border-bottom:1px solid #e2e2e2;padding:2px;';

  /* c8 ignore start */
  class VConsole {
    /**
     * @param {Element} dom
     */
    constructor (dom) {
      this.dom = dom;
      /**
       * @type {Element}
       */
      this.ccontainer = this.dom;
      this.depth = 0;
      vconsoles.add(this);
    }

    /**
     * @param {Array<string|Symbol|Object|number>} args
     * @param {boolean} collapsed
     */
    group (args, collapsed = false) {
      enqueue(() => {
        const triangleDown = element('span', [
          create$4('hidden', collapsed),
          create$4('style', 'color:grey;font-size:120%;')
        ], [text('▼')]);
        const triangleRight = element('span', [
          create$4('hidden', !collapsed),
          create$4('style', 'color:grey;font-size:125%;')
        ], [text('▶')]);
        const content = element(
          'div',
          [create$4(
            'style',
            `${lineStyle};padding-left:${this.depth * 10}px`
          )],
          [triangleDown, triangleRight, text(' ')].concat(
            _computeLineSpans(args)
          )
        );
        const nextContainer = element('div', [
          create$4('hidden', collapsed)
        ]);
        const nextLine = element('div', [], [content, nextContainer]);
        append(this.ccontainer, [nextLine]);
        this.ccontainer = nextContainer;
        this.depth++;
        // when header is clicked, collapse/uncollapse container
        addEventListener(content, 'click', (_event) => {
          nextContainer.toggleAttribute('hidden');
          triangleDown.toggleAttribute('hidden');
          triangleRight.toggleAttribute('hidden');
        });
      });
    }

    /**
     * @param {Array<string|Symbol|Object|number>} args
     */
    groupCollapsed (args) {
      this.group(args, true);
    }

    groupEnd () {
      enqueue(() => {
        if (this.depth > 0) {
          this.depth--;
          // @ts-ignore
          this.ccontainer = this.ccontainer.parentElement.parentElement;
        }
      });
    }

    /**
     * @param {Array<string|Symbol|Object|number>} args
     */
    print (args) {
      enqueue(() => {
        append(this.ccontainer, [
          element('div', [
            create$4(
              'style',
              `${lineStyle};padding-left:${this.depth * 10}px`
            )
          ], _computeLineSpans(args))
        ]);
      });
    }

    /**
     * @param {Error} err
     */
    printError (err) {
      this.print([RED, BOLD, err.toString()]);
    }

    /**
     * @param {string} url
     * @param {number} height
     */
    printImg (url, height) {
      enqueue(() => {
        append(this.ccontainer, [
          element('img', [
            create$4('src', url),
            create$4('height', `${round(height * 1.5)}px`)
          ])
        ]);
      });
    }

    /**
     * @param {Node} node
     */
    printDom (node) {
      enqueue(() => {
        append(this.ccontainer, [node]);
      });
    }

    destroy () {
      enqueue(() => {
        vconsoles.delete(this);
      });
    }
  }
  /* c8 ignore stop */

  /**
   * @param {Element} dom
   */
  /* c8 ignore next */
  const createVConsole = (dom) => new VConsole(dom);

  /* eslint-env browser */

  /**
   * Binary data constants.
   *
   * @module binary
   */

  /**
   * n-th bit activated.
   *
   * @type {number}
   */
  const BIT1 = 1;
  const BIT2 = 2;
  const BIT3 = 4;
  const BIT4 = 8;
  const BIT6 = 32;
  const BIT7 = 64;
  const BIT8 = 128;
  const BITS5 = 31;
  const BITS6 = 63;
  const BITS7 = 127;
  /**
   * @type {number}
   */
  const BITS31 = 0x7FFFFFFF;
  /**
   * @type {number}
   */
  const BITS32 = 0xFFFFFFFF;

  /* eslint-env browser */

  const getRandomValues = crypto.getRandomValues.bind(crypto);

  /**
   * Isomorphic module for true random numbers / buffers / uuids.
   *
   * Attention: falls back to Math.random if the browser does not support crypto.
   *
   * @module random
   */


  const uint32 = () => getRandomValues(new Uint32Array(1))[0];

  // @ts-ignore
  const uuidv4Template = [1e7] + -1e3 + -4e3 + -8e3 + -1e11;

  /**
   * @return {string}
   */
  const uuidv4 = () => uuidv4Template.replace(/[018]/g, /** @param {number} c */ c =>
    (c ^ uint32() & 15 >> c / 4).toString(16)
  );

  /**
   * @module prng
   */


  /**
   * Xorshift32 is a very simple but elegang PRNG with a period of `2^32-1`.
   */
  class Xorshift32 {
    /**
     * @param {number} seed Unsigned 32 bit number
     */
    constructor (seed) {
      this.seed = seed;
      /**
       * @type {number}
       */
      this._state = seed;
    }

    /**
     * Generate a random signed integer.
     *
     * @return {Number} A 32 bit signed integer.
     */
    next () {
      let x = this._state;
      x ^= x << 13;
      x ^= x >> 17;
      x ^= x << 5;
      this._state = x;
      return (x >>> 0) / (BITS32 + 1)
    }
  }

  /**
   * @module prng
   */


  /**
   * This is a variant of xoroshiro128plus - the fastest full-period generator passing BigCrush without systematic failures.
   *
   * This implementation follows the idea of the original xoroshiro128plus implementation,
   * but is optimized for the JavaScript runtime. I.e.
   * * The operations are performed on 32bit integers (the original implementation works with 64bit values).
   * * The initial 128bit state is computed based on a 32bit seed and Xorshift32.
   * * This implementation returns two 32bit values based on the 64bit value that is computed by xoroshiro128plus.
   *   Caution: The last addition step works slightly different than in the original implementation - the add carry of the
   *   first 32bit addition is not carried over to the last 32bit.
   *
   * [Reference implementation](http://vigna.di.unimi.it/xorshift/xoroshiro128plus.c)
   */
  class Xoroshiro128plus {
    /**
     * @param {number} seed Unsigned 32 bit number
     */
    constructor (seed) {
      this.seed = seed;
      // This is a variant of Xoroshiro128plus to fill the initial state
      const xorshift32 = new Xorshift32(seed);
      this.state = new Uint32Array(4);
      for (let i = 0; i < 4; i++) {
        this.state[i] = xorshift32.next() * BITS32;
      }
      this._fresh = true;
    }

    /**
     * @return {number} Float/Double in [0,1)
     */
    next () {
      const state = this.state;
      if (this._fresh) {
        this._fresh = false;
        return ((state[0] + state[2]) >>> 0) / (BITS32 + 1)
      } else {
        this._fresh = true;
        const s0 = state[0];
        const s1 = state[1];
        const s2 = state[2] ^ s0;
        const s3 = state[3] ^ s1;
        // function js_rotl (x, k) {
        //   k = k - 32
        //   const x1 = x[0]
        //   const x2 = x[1]
        //   x[0] = x2 << k | x1 >>> (32 - k)
        //   x[1] = x1 << k | x2 >>> (32 - k)
        // }
        // rotl(s0, 55) // k = 23 = 55 - 32; j = 9 =  32 - 23
        state[0] = (s1 << 23 | s0 >>> 9) ^ s2 ^ (s2 << 14 | s3 >>> 18);
        state[1] = (s0 << 23 | s1 >>> 9) ^ s3 ^ (s3 << 14);
        // rol(s1, 36) // k = 4 = 36 - 32; j = 23 = 32 - 9
        state[2] = s3 << 4 | s2 >>> 28;
        state[3] = s2 << 4 | s3 >>> 28;
        return (((state[1] + state[3]) >>> 0) / (BITS32 + 1))
      }
    }
  }

  /*
  // Reference implementation
  // Source: http://vigna.di.unimi.it/xorshift/xoroshiro128plus.c
  // By David Blackman and Sebastiano Vigna
  // Who published the reference implementation under Public Domain (CC0)

  #include <stdint.h>
  #include <stdio.h>

  uint64_t s[2];

  static inline uint64_t rotl(const uint64_t x, int k) {
      return (x << k) | (x >> (64 - k));
  }

  uint64_t next(void) {
      const uint64_t s0 = s[0];
      uint64_t s1 = s[1];
      s1 ^= s0;
      s[0] = rotl(s0, 55) ^ s1 ^ (s1 << 14); // a, b
      s[1] = rotl(s1, 36); // c
      return (s[0] + s[1]) & 0xFFFFFFFF;
  }

  int main(void)
  {
      int i;
      s[0] = 1111 | (1337ul << 32);
      s[1] = 1234 | (9999ul << 32);

      printf("1000 outputs of genrand_int31()\n");
      for (i=0; i<100; i++) {
          printf("%10lu ", i);
          printf("%10lu ", next());
          printf("- %10lu ", s[0] >> 32);
          printf("%10lu ", (s[0] << 32) >> 32);
          printf("%10lu ", s[1] >> 32);
          printf("%10lu ", (s[1] << 32) >> 32);
          printf("\n");
          // if (i%5==4) printf("\n");
      }
      return 0;
  }
  */

  /**
   * Utility helpers for working with numbers.
   *
   * @module number
   */


  const MAX_SAFE_INTEGER = Number.MAX_SAFE_INTEGER;

  /* c8 ignore next */
  const isInteger = Number.isInteger || (num => typeof num === 'number' && isFinite(num) && floor(num) === num);

  /**
   * Efficient schema-less binary encoding with support for variable length encoding.
   *
   * Use [lib0/encoding] with [lib0/decoding]. Every encoding function has a corresponding decoding function.
   *
   * Encodes numbers in little-endian order (least to most significant byte order)
   * and is compatible with Golang's binary encoding (https://golang.org/pkg/encoding/binary/)
   * which is also used in Protocol Buffers.
   *
   * ```js
   * // encoding step
   * const encoder = encoding.createEncoder()
   * encoding.writeVarUint(encoder, 256)
   * encoding.writeVarString(encoder, 'Hello world!')
   * const buf = encoding.toUint8Array(encoder)
   * ```
   *
   * ```js
   * // decoding step
   * const decoder = decoding.createDecoder(buf)
   * decoding.readVarUint(decoder) // => 256
   * decoding.readVarString(decoder) // => 'Hello world!'
   * decoding.hasContent(decoder) // => false - all data is read
   * ```
   *
   * @module encoding
   */


  /**
   * A BinaryEncoder handles the encoding to an Uint8Array.
   */
  class Encoder {
    constructor () {
      this.cpos = 0;
      this.cbuf = new Uint8Array(100);
      /**
       * @type {Array<Uint8Array>}
       */
      this.bufs = [];
    }
  }

  /**
   * @function
   * @return {Encoder}
   */
  const createEncoder = () => new Encoder();

  /**
   * The current length of the encoded data.
   *
   * @function
   * @param {Encoder} encoder
   * @return {number}
   */
  const length = encoder => {
    let len = encoder.cpos;
    for (let i = 0; i < encoder.bufs.length; i++) {
      len += encoder.bufs[i].length;
    }
    return len
  };

  /**
   * Transform to Uint8Array.
   *
   * @function
   * @param {Encoder} encoder
   * @return {Uint8Array} The created ArrayBuffer.
   */
  const toUint8Array = encoder => {
    const uint8arr = new Uint8Array(length(encoder));
    let curPos = 0;
    for (let i = 0; i < encoder.bufs.length; i++) {
      const d = encoder.bufs[i];
      uint8arr.set(d, curPos);
      curPos += d.length;
    }
    uint8arr.set(createUint8ArrayViewFromArrayBuffer(encoder.cbuf.buffer, 0, encoder.cpos), curPos);
    return uint8arr
  };

  /**
   * Verify that it is possible to write `len` bytes wtihout checking. If
   * necessary, a new Buffer with the required length is attached.
   *
   * @param {Encoder} encoder
   * @param {number} len
   */
  const verifyLen = (encoder, len) => {
    const bufferLen = encoder.cbuf.length;
    if (bufferLen - encoder.cpos < len) {
      encoder.bufs.push(createUint8ArrayViewFromArrayBuffer(encoder.cbuf.buffer, 0, encoder.cpos));
      encoder.cbuf = new Uint8Array(max(bufferLen, len) * 2);
      encoder.cpos = 0;
    }
  };

  /**
   * Write one byte to the encoder.
   *
   * @function
   * @param {Encoder} encoder
   * @param {number} num The byte that is to be encoded.
   */
  const write = (encoder, num) => {
    const bufferLen = encoder.cbuf.length;
    if (encoder.cpos === bufferLen) {
      encoder.bufs.push(encoder.cbuf);
      encoder.cbuf = new Uint8Array(bufferLen * 2);
      encoder.cpos = 0;
    }
    encoder.cbuf[encoder.cpos++] = num;
  };

  /**
   * Write one byte as an unsigned integer.
   *
   * @function
   * @param {Encoder} encoder
   * @param {number} num The number that is to be encoded.
   */
  const writeUint8 = write;

  /**
   * Write a variable length unsigned integer. Max encodable integer is 2^53.
   *
   * @function
   * @param {Encoder} encoder
   * @param {number} num The number that is to be encoded.
   */
  const writeVarUint = (encoder, num) => {
    while (num > BITS7) {
      write(encoder, BIT8 | (BITS7 & num));
      num = floor(num / 128); // shift >>> 7
    }
    write(encoder, BITS7 & num);
  };

  /**
   * Write a variable length integer.
   *
   * We use the 7th bit instead for signaling that this is a negative number.
   *
   * @function
   * @param {Encoder} encoder
   * @param {number} num The number that is to be encoded.
   */
  const writeVarInt = (encoder, num) => {
    const isNegative = isNegativeZero(num);
    if (isNegative) {
      num = -num;
    }
    //             |- whether to continue reading         |- whether is negative     |- number
    write(encoder, (num > BITS6 ? BIT8 : 0) | (isNegative ? BIT7 : 0) | (BITS6 & num));
    num = floor(num / 64); // shift >>> 6
    // We don't need to consider the case of num === 0 so we can use a different
    // pattern here than above.
    while (num > 0) {
      write(encoder, (num > BITS7 ? BIT8 : 0) | (BITS7 & num));
      num = floor(num / 128); // shift >>> 7
    }
  };

  /**
   * A cache to store strings temporarily
   */
  const _strBuffer = new Uint8Array(30000);
  const _maxStrBSize = _strBuffer.length / 3;

  /**
   * Write a variable length string.
   *
   * @function
   * @param {Encoder} encoder
   * @param {String} str The string that is to be encoded.
   */
  const _writeVarStringNative = (encoder, str) => {
    if (str.length < _maxStrBSize) {
      // We can encode the string into the existing buffer
      /* c8 ignore next */
      const written = utf8TextEncoder.encodeInto(str, _strBuffer).written || 0;
      writeVarUint(encoder, written);
      for (let i = 0; i < written; i++) {
        write(encoder, _strBuffer[i]);
      }
    } else {
      writeVarUint8Array(encoder, encodeUtf8(str));
    }
  };

  /**
   * Write a variable length string.
   *
   * @function
   * @param {Encoder} encoder
   * @param {String} str The string that is to be encoded.
   */
  const _writeVarStringPolyfill = (encoder, str) => {
    const encodedString = unescape(encodeURIComponent(str));
    const len = encodedString.length;
    writeVarUint(encoder, len);
    for (let i = 0; i < len; i++) {
      write(encoder, /** @type {number} */ (encodedString.codePointAt(i)));
    }
  };

  /**
   * Write a variable length string.
   *
   * @function
   * @param {Encoder} encoder
   * @param {String} str The string that is to be encoded.
   */
  /* c8 ignore next */
  const writeVarString = (utf8TextEncoder && /** @type {any} */ (utf8TextEncoder).encodeInto) ? _writeVarStringNative : _writeVarStringPolyfill;

  /**
   * Append fixed-length Uint8Array to the encoder.
   *
   * @function
   * @param {Encoder} encoder
   * @param {Uint8Array} uint8Array
   */
  const writeUint8Array = (encoder, uint8Array) => {
    const bufferLen = encoder.cbuf.length;
    const cpos = encoder.cpos;
    const leftCopyLen = min(bufferLen - cpos, uint8Array.length);
    const rightCopyLen = uint8Array.length - leftCopyLen;
    encoder.cbuf.set(uint8Array.subarray(0, leftCopyLen), cpos);
    encoder.cpos += leftCopyLen;
    if (rightCopyLen > 0) {
      // Still something to write, write right half..
      // Append new buffer
      encoder.bufs.push(encoder.cbuf);
      // must have at least size of remaining buffer
      encoder.cbuf = new Uint8Array(max(bufferLen * 2, rightCopyLen));
      // copy array
      encoder.cbuf.set(uint8Array.subarray(leftCopyLen));
      encoder.cpos = rightCopyLen;
    }
  };

  /**
   * Append an Uint8Array to Encoder.
   *
   * @function
   * @param {Encoder} encoder
   * @param {Uint8Array} uint8Array
   */
  const writeVarUint8Array = (encoder, uint8Array) => {
    writeVarUint(encoder, uint8Array.byteLength);
    writeUint8Array(encoder, uint8Array);
  };

  /**
   * Create an DataView of the next `len` bytes. Use it to write data after
   * calling this function.
   *
   * ```js
   * // write float32 using DataView
   * const dv = writeOnDataView(encoder, 4)
   * dv.setFloat32(0, 1.1)
   * // read float32 using DataView
   * const dv = readFromDataView(encoder, 4)
   * dv.getFloat32(0) // => 1.100000023841858 (leaving it to the reader to find out why this is the correct result)
   * ```
   *
   * @param {Encoder} encoder
   * @param {number} len
   * @return {DataView}
   */
  const writeOnDataView = (encoder, len) => {
    verifyLen(encoder, len);
    const dview = new DataView(encoder.cbuf.buffer, encoder.cpos, len);
    encoder.cpos += len;
    return dview
  };

  /**
   * @param {Encoder} encoder
   * @param {number} num
   */
  const writeFloat32 = (encoder, num) => writeOnDataView(encoder, 4).setFloat32(0, num, false);

  /**
   * @param {Encoder} encoder
   * @param {number} num
   */
  const writeFloat64 = (encoder, num) => writeOnDataView(encoder, 8).setFloat64(0, num, false);

  /**
   * @param {Encoder} encoder
   * @param {bigint} num
   */
  const writeBigInt64 = (encoder, num) => /** @type {any} */ (writeOnDataView(encoder, 8)).setBigInt64(0, num, false);

  const floatTestBed = new DataView(new ArrayBuffer(4));
  /**
   * Check if a number can be encoded as a 32 bit float.
   *
   * @param {number} num
   * @return {boolean}
   */
  const isFloat32 = num => {
    floatTestBed.setFloat32(0, num);
    return floatTestBed.getFloat32(0) === num
  };

  /**
   * Encode data with efficient binary format.
   *
   * Differences to JSON:
   * • Transforms data to a binary format (not to a string)
   * • Encodes undefined, NaN, and ArrayBuffer (these can't be represented in JSON)
   * • Numbers are efficiently encoded either as a variable length integer, as a
   *   32 bit float, as a 64 bit float, or as a 64 bit bigint.
   *
   * Encoding table:
   *
   * | Data Type           | Prefix   | Encoding Method    | Comment |
   * | ------------------- | -------- | ------------------ | ------- |
   * | undefined           | 127      |                    | Functions, symbol, and everything that cannot be identified is encoded as undefined |
   * | null                | 126      |                    | |
   * | integer             | 125      | writeVarInt        | Only encodes 32 bit signed integers |
   * | float32             | 124      | writeFloat32       | |
   * | float64             | 123      | writeFloat64       | |
   * | bigint              | 122      | writeBigInt64      | |
   * | boolean (false)     | 121      |                    | True and false are different data types so we save the following byte |
   * | boolean (true)      | 120      |                    | - 0b01111000 so the last bit determines whether true or false |
   * | string              | 119      | writeVarString     | |
   * | object<string,any>  | 118      | custom             | Writes {length} then {length} key-value pairs |
   * | array<any>          | 117      | custom             | Writes {length} then {length} json values |
   * | Uint8Array          | 116      | writeVarUint8Array | We use Uint8Array for any kind of binary data |
   *
   * Reasons for the decreasing prefix:
   * We need the first bit for extendability (later we may want to encode the
   * prefix with writeVarUint). The remaining 7 bits are divided as follows:
   * [0-30]   the beginning of the data range is used for custom purposes
   *          (defined by the function that uses this library)
   * [31-127] the end of the data range is used for data encoding by
   *          lib0/encoding.js
   *
   * @param {Encoder} encoder
   * @param {undefined|null|number|bigint|boolean|string|Object<string,any>|Array<any>|Uint8Array} data
   */
  const writeAny = (encoder, data) => {
    switch (typeof data) {
      case 'string':
        // TYPE 119: STRING
        write(encoder, 119);
        writeVarString(encoder, data);
        break
      case 'number':
        if (isInteger(data) && abs(data) <= BITS31) {
          // TYPE 125: INTEGER
          write(encoder, 125);
          writeVarInt(encoder, data);
        } else if (isFloat32(data)) {
          // TYPE 124: FLOAT32
          write(encoder, 124);
          writeFloat32(encoder, data);
        } else {
          // TYPE 123: FLOAT64
          write(encoder, 123);
          writeFloat64(encoder, data);
        }
        break
      case 'bigint':
        // TYPE 122: BigInt
        write(encoder, 122);
        writeBigInt64(encoder, data);
        break
      case 'object':
        if (data === null) {
          // TYPE 126: null
          write(encoder, 126);
        } else if (isArray(data)) {
          // TYPE 117: Array
          write(encoder, 117);
          writeVarUint(encoder, data.length);
          for (let i = 0; i < data.length; i++) {
            writeAny(encoder, data[i]);
          }
        } else if (data instanceof Uint8Array) {
          // TYPE 116: ArrayBuffer
          write(encoder, 116);
          writeVarUint8Array(encoder, data);
        } else {
          // TYPE 118: Object
          write(encoder, 118);
          const keys = Object.keys(data);
          writeVarUint(encoder, keys.length);
          for (let i = 0; i < keys.length; i++) {
            const key = keys[i];
            writeVarString(encoder, key);
            writeAny(encoder, data[key]);
          }
        }
        break
      case 'boolean':
        // TYPE 120/121: boolean (true/false)
        write(encoder, data ? 120 : 121);
        break
      default:
        // TYPE 127: undefined
        write(encoder, 127);
    }
  };

  /**
   * Now come a few stateful encoder that have their own classes.
   */

  /**
   * Basic Run Length Encoder - a basic compression implementation.
   *
   * Encodes [1,1,1,7] to [1,3,7,1] (3 times 1, 1 time 7). This encoder might do more harm than good if there are a lot of values that are not repeated.
   *
   * It was originally used for image compression. Cool .. article http://csbruce.com/cbm/transactor/pdfs/trans_v7_i06.pdf
   *
   * @note T must not be null!
   *
   * @template T
   */
  class RleEncoder extends Encoder {
    /**
     * @param {function(Encoder, T):void} writer
     */
    constructor (writer) {
      super();
      /**
       * The writer
       */
      this.w = writer;
      /**
       * Current state
       * @type {T|null}
       */
      this.s = null;
      this.count = 0;
    }

    /**
     * @param {T} v
     */
    write (v) {
      if (this.s === v) {
        this.count++;
      } else {
        if (this.count > 0) {
          // flush counter, unless this is the first value (count = 0)
          writeVarUint(this, this.count - 1); // since count is always > 0, we can decrement by one. non-standard encoding ftw
        }
        this.count = 1;
        // write first value
        this.w(this, v);
        this.s = v;
      }
    }
  }

  /**
   * @param {UintOptRleEncoder} encoder
   */
  const flushUintOptRleEncoder = encoder => {
    if (encoder.count > 0) {
      // flush counter, unless this is the first value (count = 0)
      // case 1: just a single value. set sign to positive
      // case 2: write several values. set sign to negative to indicate that there is a length coming
      writeVarInt(encoder.encoder, encoder.count === 1 ? encoder.s : -encoder.s);
      if (encoder.count > 1) {
        writeVarUint(encoder.encoder, encoder.count - 2); // since count is always > 1, we can decrement by one. non-standard encoding ftw
      }
    }
  };

  /**
   * Optimized Rle encoder that does not suffer from the mentioned problem of the basic Rle encoder.
   *
   * Internally uses VarInt encoder to write unsigned integers. If the input occurs multiple times, we write
   * write it as a negative number. The UintOptRleDecoder then understands that it needs to read a count.
   *
   * Encodes [1,2,3,3,3] as [1,2,-3,3] (once 1, once 2, three times 3)
   */
  class UintOptRleEncoder {
    constructor () {
      this.encoder = new Encoder();
      /**
       * @type {number}
       */
      this.s = 0;
      this.count = 0;
    }

    /**
     * @param {number} v
     */
    write (v) {
      if (this.s === v) {
        this.count++;
      } else {
        flushUintOptRleEncoder(this);
        this.count = 1;
        this.s = v;
      }
    }

    toUint8Array () {
      flushUintOptRleEncoder(this);
      return toUint8Array(this.encoder)
    }
  }

  /**
   * @param {IntDiffOptRleEncoder} encoder
   */
  const flushIntDiffOptRleEncoder = encoder => {
    if (encoder.count > 0) {
      //          31 bit making up the diff | wether to write the counter
      // const encodedDiff = encoder.diff << 1 | (encoder.count === 1 ? 0 : 1)
      const encodedDiff = encoder.diff * 2 + (encoder.count === 1 ? 0 : 1);
      // flush counter, unless this is the first value (count = 0)
      // case 1: just a single value. set first bit to positive
      // case 2: write several values. set first bit to negative to indicate that there is a length coming
      writeVarInt(encoder.encoder, encodedDiff);
      if (encoder.count > 1) {
        writeVarUint(encoder.encoder, encoder.count - 2); // since count is always > 1, we can decrement by one. non-standard encoding ftw
      }
    }
  };

  /**
   * A combination of the IntDiffEncoder and the UintOptRleEncoder.
   *
   * The count approach is similar to the UintDiffOptRleEncoder, but instead of using the negative bitflag, it encodes
   * in the LSB whether a count is to be read. Therefore this Encoder only supports 31 bit integers!
   *
   * Encodes [1, 2, 3, 2] as [3, 1, 6, -1] (more specifically [(1 << 1) | 1, (3 << 0) | 0, -1])
   *
   * Internally uses variable length encoding. Contrary to normal UintVar encoding, the first byte contains:
   * * 1 bit that denotes whether the next value is a count (LSB)
   * * 1 bit that denotes whether this value is negative (MSB - 1)
   * * 1 bit that denotes whether to continue reading the variable length integer (MSB)
   *
   * Therefore, only five bits remain to encode diff ranges.
   *
   * Use this Encoder only when appropriate. In most cases, this is probably a bad idea.
   */
  class IntDiffOptRleEncoder {
    constructor () {
      this.encoder = new Encoder();
      /**
       * @type {number}
       */
      this.s = 0;
      this.count = 0;
      this.diff = 0;
    }

    /**
     * @param {number} v
     */
    write (v) {
      if (this.diff === v - this.s) {
        this.s = v;
        this.count++;
      } else {
        flushIntDiffOptRleEncoder(this);
        this.count = 1;
        this.diff = v - this.s;
        this.s = v;
      }
    }

    toUint8Array () {
      flushIntDiffOptRleEncoder(this);
      return toUint8Array(this.encoder)
    }
  }

  /**
   * Optimized String Encoder.
   *
   * Encoding many small strings in a simple Encoder is not very efficient. The function call to decode a string takes some time and creates references that must be eventually deleted.
   * In practice, when decoding several million small strings, the GC will kick in more and more often to collect orphaned string objects (or maybe there is another reason?).
   *
   * This string encoder solves the above problem. All strings are concatenated and written as a single string using a single encoding call.
   *
   * The lengths are encoded using a UintOptRleEncoder.
   */
  class StringEncoder {
    constructor () {
      /**
       * @type {Array<string>}
       */
      this.sarr = [];
      this.s = '';
      this.lensE = new UintOptRleEncoder();
    }

    /**
     * @param {string} string
     */
    write (string) {
      this.s += string;
      if (this.s.length > 19) {
        this.sarr.push(this.s);
        this.s = '';
      }
      this.lensE.write(string.length);
    }

    toUint8Array () {
      const encoder = new Encoder();
      this.sarr.push(this.s);
      this.s = '';
      writeVarString(encoder, this.sarr.join(''));
      writeUint8Array(encoder, this.lensE.toUint8Array());
      return toUint8Array(encoder)
    }
  }

  /**
   * Error helpers.
   *
   * @module error
   */

  /**
   * @param {string} s
   * @return {Error}
   */
  /* c8 ignore next */
  const create$2 = s => new Error(s);

  /**
   * @throws {Error}
   * @return {never}
   */
  /* c8 ignore next 3 */
  const methodUnimplemented = () => {
    throw create$2('Method unimplemented')
  };

  /**
   * @throws {Error}
   * @return {never}
   */
  /* c8 ignore next 3 */
  const unexpectedCase = () => {
    throw create$2('Unexpected case')
  };

  /**
   * Efficient schema-less binary decoding with support for variable length encoding.
   *
   * Use [lib0/decoding] with [lib0/encoding]. Every encoding function has a corresponding decoding function.
   *
   * Encodes numbers in little-endian order (least to most significant byte order)
   * and is compatible with Golang's binary encoding (https://golang.org/pkg/encoding/binary/)
   * which is also used in Protocol Buffers.
   *
   * ```js
   * // encoding step
   * const encoder = encoding.createEncoder()
   * encoding.writeVarUint(encoder, 256)
   * encoding.writeVarString(encoder, 'Hello world!')
   * const buf = encoding.toUint8Array(encoder)
   * ```
   *
   * ```js
   * // decoding step
   * const decoder = decoding.createDecoder(buf)
   * decoding.readVarUint(decoder) // => 256
   * decoding.readVarString(decoder) // => 'Hello world!'
   * decoding.hasContent(decoder) // => false - all data is read
   * ```
   *
   * @module decoding
   */


  const errorUnexpectedEndOfArray = create$2('Unexpected end of array');
  const errorIntegerOutOfRange = create$2('Integer out of Range');

  /**
   * A Decoder handles the decoding of an Uint8Array.
   */
  class Decoder {
    /**
     * @param {Uint8Array} uint8Array Binary data to decode
     */
    constructor (uint8Array) {
      /**
       * Decoding target.
       *
       * @type {Uint8Array}
       */
      this.arr = uint8Array;
      /**
       * Current decoding position.
       *
       * @type {number}
       */
      this.pos = 0;
    }
  }

  /**
   * @function
   * @param {Uint8Array} uint8Array
   * @return {Decoder}
   */
  const createDecoder = uint8Array => new Decoder(uint8Array);

  /**
   * Create an Uint8Array view of the next `len` bytes and advance the position by `len`.
   *
   * Important: The Uint8Array still points to the underlying ArrayBuffer. Make sure to discard the result as soon as possible to prevent any memory leaks.
   *            Use `buffer.copyUint8Array` to copy the result into a new Uint8Array.
   *
   * @function
   * @param {Decoder} decoder The decoder instance
   * @param {number} len The length of bytes to read
   * @return {Uint8Array}
   */
  const readUint8Array = (decoder, len) => {
    const view = createUint8ArrayViewFromArrayBuffer(decoder.arr.buffer, decoder.pos + decoder.arr.byteOffset, len);
    decoder.pos += len;
    return view
  };

  /**
   * Read variable length Uint8Array.
   *
   * Important: The Uint8Array still points to the underlying ArrayBuffer. Make sure to discard the result as soon as possible to prevent any memory leaks.
   *            Use `buffer.copyUint8Array` to copy the result into a new Uint8Array.
   *
   * @function
   * @param {Decoder} decoder
   * @return {Uint8Array}
   */
  const readVarUint8Array = decoder => readUint8Array(decoder, readVarUint(decoder));

  /**
   * Read one byte as unsigned integer.
   * @function
   * @param {Decoder} decoder The decoder instance
   * @return {number} Unsigned 8-bit integer
   */
  const readUint8 = decoder => decoder.arr[decoder.pos++];

  /**
   * Read unsigned integer (32bit) with variable length.
   * 1/8th of the storage is used as encoding overhead.
   *  * numbers < 2^7 is stored in one bytlength
   *  * numbers < 2^14 is stored in two bylength
   *
   * @function
   * @param {Decoder} decoder
   * @return {number} An unsigned integer.length
   */
  const readVarUint = decoder => {
    let num = 0;
    let mult = 1;
    const len = decoder.arr.length;
    while (decoder.pos < len) {
      const r = decoder.arr[decoder.pos++];
      // num = num | ((r & binary.BITS7) << len)
      num = num + (r & BITS7) * mult; // shift $r << (7*#iterations) and add it to num
      mult *= 128; // next iteration, shift 7 "more" to the left
      if (r < BIT8) {
        return num
      }
      /* c8 ignore start */
      if (num > MAX_SAFE_INTEGER) {
        throw errorIntegerOutOfRange
      }
      /* c8 ignore stop */
    }
    throw errorUnexpectedEndOfArray
  };

  /**
   * We don't test this function anymore as we use native decoding/encoding by default now.
   * Better not modify this anymore..
   *
   * Transforming utf8 to a string is pretty expensive. The code performs 10x better
   * when String.fromCodePoint is fed with all characters as arguments.
   * But most environments have a maximum number of arguments per functions.
   * For effiency reasons we apply a maximum of 10000 characters at once.
   *
   * @function
   * @param {Decoder} decoder
   * @return {String} The read String.
   */
  /* c8 ignore start */
  const _readVarStringPolyfill = decoder => {
    let remainingLen = readVarUint(decoder);
    if (remainingLen === 0) {
      return ''
    } else {
      let encodedString = String.fromCodePoint(readUint8(decoder)); // remember to decrease remainingLen
      if (--remainingLen < 100) { // do not create a Uint8Array for small strings
        while (remainingLen--) {
          encodedString += String.fromCodePoint(readUint8(decoder));
        }
      } else {
        while (remainingLen > 0) {
          const nextLen = remainingLen < 10000 ? remainingLen : 10000;
          // this is dangerous, we create a fresh array view from the existing buffer
          const bytes = decoder.arr.subarray(decoder.pos, decoder.pos + nextLen);
          decoder.pos += nextLen;
          // Starting with ES5.1 we can supply a generic array-like object as arguments
          encodedString += String.fromCodePoint.apply(null, /** @type {any} */ (bytes));
          remainingLen -= nextLen;
        }
      }
      return decodeURIComponent(escape(encodedString))
    }
  };
  /* c8 ignore stop */

  /**
   * @function
   * @param {Decoder} decoder
   * @return {String} The read String
   */
  const _readVarStringNative = decoder =>
    /** @type any */ (utf8TextDecoder).decode(readVarUint8Array(decoder));

  /**
   * Read string of variable length
   * * varUint is used to store the length of the string
   *
   * @function
   * @param {Decoder} decoder
   * @return {String} The read String
   *
   */
  /* c8 ignore next */
  const readVarString = utf8TextDecoder ? _readVarStringNative : _readVarStringPolyfill;

  /**
   * Utility functions to work with buffers (Uint8Array).
   *
   * @module buffer
   */


  /**
   * Create Uint8Array with initial content from buffer
   *
   * @param {ArrayBuffer} buffer
   * @param {number} byteOffset
   * @param {number} length
   */
  const createUint8ArrayViewFromArrayBuffer = (buffer, byteOffset, length) => new Uint8Array(buffer, byteOffset, length);

  /**
   * Fast Pseudo Random Number Generators.
   *
   * Given a seed a PRNG generates a sequence of numbers that cannot be reasonably predicted.
   * Two PRNGs must generate the same random sequence of numbers if  given the same seed.
   *
   * @module prng
   */


  /**
   * Description of the function
   *  @callback generatorNext
   *  @return {number} A random float in the cange of [0,1)
   */

  /**
   * A random type generator.
   *
   * @typedef {Object} PRNG
   * @property {generatorNext} next Generate new number
   */
  const DefaultPRNG = Xoroshiro128plus;

  /**
   * Create a Xoroshiro128plus Pseudo-Random-Number-Generator.
   * This is the fastest full-period generator passing BigCrush without systematic failures.
   * But there are more PRNGs available in ./PRNG/.
   *
   * @param {number} seed A positive 32bit integer. Do not use negative numbers.
   * @return {PRNG}
   */
  const create$1 = seed => new DefaultPRNG(seed);
  /* c8 ignore stop */

  /**
   * Utility helpers for generating statistics.
   *
   * @module statistics
   */


  /**
   * @param {Array<number>} arr Array of values
   * @return {number} Returns null if the array is empty
   */
  const median = arr => arr.length === 0 ? NaN : (arr.length % 2 === 1 ? arr[(arr.length - 1) / 2] : (arr[floor((arr.length - 1) / 2)] + arr[ceil((arr.length - 1) / 2)]) / 2);

  /**
   * @param {Array<number>} arr
   * @return {number}
   */
  const average = arr => arr.reduce(add, 0) / arr.length;

  /**
   * Utility helpers to work with promises.
   *
   * @module promise
   */


  /**
   * @template T
   * @callback PromiseResolve
   * @param {T|PromiseLike<T>} [result]
   */

  /**
   * @template T
   * @param {function(PromiseResolve<T>,function(Error):void):any} f
   * @return {Promise<T>}
   */
  const create = f => /** @type {Promise<T>} */ (new Promise(f));

  /**
   * `Promise.all` wait for all promises in the array to resolve and return the result
   * @template {unknown[] | []} PS
   *
   * @param {PS} ps
   * @return {Promise<{ -readonly [P in keyof PS]: Awaited<PS[P]> }>}
   */
  Promise.all.bind(Promise);

  /**
   * Checks if an object is a promise using ducktyping.
   *
   * Promises are often polyfilled, so it makes sense to add some additional guarantees if the user of this
   * library has some insane environment where global Promise objects are overwritten.
   *
   * @param {any} p
   * @return {boolean}
   */
  const isPromise = p => p instanceof Promise || (p && p.then && p.catch && p.finally);

  /* eslint-env browser */

  const measure = performance.measure.bind(performance);
  const now = performance.now.bind(performance);
  const mark = performance.mark.bind(performance);

  /**
   * Testing framework with support for generating tests.
   *
   * ```js
   * // test.js template for creating a test executable
   * import { runTests } from 'lib0/testing'
   * import * as log from 'lib0/logging'
   * import * as mod1 from './mod1.test.js'
   * import * as mod2 from './mod2.test.js'

   * import { isBrowser, isNode } from 'lib0/environment.js'
   *
   * if (isBrowser) {
   *   // optional: if this is ran in the browser, attach a virtual console to the dom
   *   log.createVConsole(document.body)
   * }
   *
   * runTests({
   *  mod1,
   *  mod2,
   * }).then(success => {
   *   if (isNode) {
   *     process.exit(success ? 0 : 1)
   *   }
   * })
   * ```
   *
   * ```js
   * // mod1.test.js
   * /**
   *  * runTests automatically tests all exported functions that start with "test".
   *  * The name of the function should be in camelCase and is used for the logging output.
   *  *
   *  * @param {t.TestCase} tc
   *  *\/
   * export const testMyFirstTest = tc => {
   *   t.compare({ a: 4 }, { a: 4 }, 'objects are equal')
   * }
   * ```
   *
   * Now you can simply run `node test.js` to run your test or run test.js in the browser.
   *
   * @module testing
   */


  hasConf('extensive');

  /* c8 ignore next */
  const envSeed = hasParam('--seed') ? Number.parseInt(getParam('--seed', '0')) : null;

  class TestCase {
    /**
     * @param {string} moduleName
     * @param {string} testName
     */
    constructor (moduleName, testName) {
      /**
       * @type {string}
       */
      this.moduleName = moduleName;
      /**
       * @type {string}
       */
      this.testName = testName;
      /**
       * This type can store custom information related to the TestCase
       *
       * @type {Map<string,any>}
       */
      this.meta = new Map();
      this._seed = null;
      this._prng = null;
    }

    resetSeed () {
      this._seed = null;
      this._prng = null;
    }

    /**
     * @type {number}
     */
    /* c8 ignore next */
    get seed () {
      /* c8 ignore else */
      if (this._seed === null) {
        /* c8 ignore next */
        this._seed = envSeed === null ? uint32() : envSeed;
      }
      return this._seed
    }

    /**
     * A PRNG for this test case. Use only this PRNG for randomness to make the test case reproducible.
     *
     * @type {prng.PRNG}
     */
    get prng () {
      /* c8 ignore else */
      if (this._prng === null) {
        this._prng = create$1(this.seed);
      }
      return this._prng
    }
  }

  const repetitionTime = Number(getParam('--repetition-time', '50'));
  /* c8 ignore next */
  const testFilter = hasParam('--filter') ? getParam('--filter', '') : null;

  /* c8 ignore next */
  const testFilterRegExp = testFilter !== null ? new RegExp(testFilter) : /.*/;

  const repeatTestRegex = /^(repeat|repeating)\s/;

  /**
   * @param {string} moduleName
   * @param {string} name
   * @param {function(TestCase):void|Promise<any>} f
   * @param {number} i
   * @param {number} numberOfTests
   */
  const run = async (moduleName, name, f, i, numberOfTests) => {
    const uncamelized = fromCamelCase(name.slice(4), ' ');
    const filtered = !testFilterRegExp.test(`[${i + 1}/${numberOfTests}] ${moduleName}: ${uncamelized}`);
    /* c8 ignore next 3 */
    if (filtered) {
      return true
    }
    const tc = new TestCase(moduleName, name);
    const repeat = repeatTestRegex.test(uncamelized);
    const groupArgs = [GREY, `[${i + 1}/${numberOfTests}] `, PURPLE, `${moduleName}: `, BLUE, uncamelized];
    /* c8 ignore next 5 */
    if (testFilter === null) {
      groupCollapsed(...groupArgs);
    } else {
      group(...groupArgs);
    }
    const times = [];
    const start = now();
    let lastTime = start;
    /**
     * @type {any}
     */
    let err = null;
    mark(`${name}-start`);
    do {
      try {
        const p = f(tc);
        if (isPromise(p)) {
          await p;
        }
      } catch (_err) {
        err = _err;
      }
      const currTime = now();
      times.push(currTime - lastTime);
      lastTime = currTime;
      if (repeat && err === null && (lastTime - start) < repetitionTime) {
        tc.resetSeed();
      } else {
        break
      }
    } while (err === null && (lastTime - start) < repetitionTime)
    mark(`${name}-end`);
    /* c8 ignore next 3 */
    if (err !== null && err.constructor !== SkipError) {
      printError(err);
    }
    measure(name, `${name}-start`, `${name}-end`);
    groupEnd();
    const duration = lastTime - start;
    let success = true;
    times.sort((a, b) => a - b);
    /* c8 ignore next 3 */
    const againMessage = isBrowser
      ? `     - ${window.location.host + window.location.pathname}?filter=\\[${i + 1}/${tc._seed === null ? '' : `&seed=${tc._seed}`}`
      : `\nrepeat: npm run test -- --filter "\\[${i + 1}/" ${tc._seed === null ? '' : `--seed ${tc._seed}`}`;
    const timeInfo = (repeat && err === null)
      ? ` - ${times.length} repetitions in ${humanizeDuration(duration)} (best: ${humanizeDuration(times[0])}, worst: ${humanizeDuration(last(times))}, median: ${humanizeDuration(median(times))}, average: ${humanizeDuration(average(times))})`
      : ` in ${humanizeDuration(duration)}`;
    if (err !== null) {
      /* c8 ignore start */
      if (err.constructor === SkipError) {
        print(GREY, BOLD, 'Skipped: ', UNBOLD, uncamelized);
      } else {
        success = false;
        print(RED, BOLD, 'Failure: ', UNBOLD, UNCOLOR, uncamelized, GREY, timeInfo, againMessage);
      }
      /* c8 ignore stop */
    } else {
      print(GREEN, BOLD, 'Success: ', UNBOLD, UNCOLOR, uncamelized, GREY, timeInfo, againMessage);
    }
    return success
  };

  /**
   * @param {any} _constructor
   * @param {any} a
   * @param {any} b
   * @param {string} path
   * @throws {TestError}
   */
  const compareValues = (_constructor, a, b, path) => {
    if (a !== b) {
      fail(`Values ${stringify(a)} and ${stringify(b)} don't match (${path})`);
    }
    return true
  };

  /**
   * @param {string?} message
   * @param {string} reason
   * @param {string} path
   * @throws {TestError}
   */
  const _failMessage = (message, reason, path) => fail(
    message === null
      ? `${reason} ${path}`
      : `${message} (${reason}) ${path}`
  );

  /**
   * @param {any} a
   * @param {any} b
   * @param {string} path
   * @param {string?} message
   * @param {function(any,any,any,string,any):boolean} customCompare
   */
  const _compare = (a, b, path, message, customCompare) => {
    // we don't use assert here because we want to test all branches (istanbul errors if one branch is not tested)
    if (a == null || b == null) {
      return compareValues(null, a, b, path)
    }
    if (a.constructor !== b.constructor) {
      _failMessage(message, 'Constructors don\'t match', path);
    }
    let success = true;
    switch (a.constructor) {
      case ArrayBuffer:
        a = new Uint8Array(a);
        b = new Uint8Array(b);
      // eslint-disable-next-line no-fallthrough
      case Uint8Array: {
        if (a.byteLength !== b.byteLength) {
          _failMessage(message, 'ArrayBuffer lengths match', path);
        }
        for (let i = 0; success && i < a.length; i++) {
          success = success && a[i] === b[i];
        }
        break
      }
      case Set: {
        if (a.size !== b.size) {
          _failMessage(message, 'Sets have different number of attributes', path);
        }
        // @ts-ignore
        a.forEach(value => {
          if (!b.has(value)) {
            _failMessage(message, `b.${path} does have ${value}`, path);
          }
        });
        break
      }
      case Map: {
        if (a.size !== b.size) {
          _failMessage(message, 'Maps have different number of attributes', path);
        }
        // @ts-ignore
        a.forEach((value, key) => {
          if (!b.has(key)) {
            _failMessage(message, `Property ${path}["${key}"] does not exist on second argument`, path);
          }
          _compare(value, b.get(key), `${path}["${key}"]`, message, customCompare);
        });
        break
      }
      case Object:
        if (length$1(a) !== length$1(b)) {
          _failMessage(message, 'Objects have a different number of attributes', path);
        }
        forEach$1(a, (value, key) => {
          if (!hasProperty(b, key)) {
            _failMessage(message, `Property ${path} does not exist on second argument`, path);
          }
          _compare(value, b[key], `${path}["${key}"]`, message, customCompare);
        });
        break
      case Array:
        if (a.length !== b.length) {
          _failMessage(message, 'Arrays have a different number of attributes', path);
        }
        // @ts-ignore
        a.forEach((value, i) => _compare(value, b[i], `${path}[${i}]`, message, customCompare));
        break
      /* c8 ignore next 4 */
      default:
        if (!customCompare(a.constructor, a, b, path, compareValues)) {
          _failMessage(message, `Values ${stringify(a)} and ${stringify(b)} don't match`, path);
        }
    }
    assert(success, message);
    return true
  };

  /**
   * @template T
   * @param {T} a
   * @param {T} b
   * @param {string?} [message]
   * @param {function(any,T,T,string,any):boolean} [customCompare]
   */
  const compare = (a, b, message = null, customCompare = compareValues) => _compare(a, b, 'obj', message, customCompare);

  /**
   * @template T
   * @param {T} property
   * @param {string?} [message]
   * @return {asserts property is NonNullable<T>}
   * @throws {TestError}
   */
  /* c8 ignore next */
  const assert = (property, message = null) => { property || fail(`Assertion failed${message !== null ? `: ${message}` : ''}`); };

  /**
   * @param {Object<string, Object<string, function(TestCase):void|Promise<any>>>} tests
   */
  const runTests = async tests => {
    /**
     * @param {string} testname
     */
    const filterTest = testname => testname.startsWith('test') || testname.startsWith('benchmark');
    const numberOfTests = map(tests, mod => map(mod, (f, fname) => /* c8 ignore next */ f && filterTest(fname) ? 1 : 0).reduce(add, 0)).reduce(add, 0);
    let successfulTests = 0;
    let testnumber = 0;
    const start = now();
    for (const modName in tests) {
      const mod = tests[modName];
      for (const fname in mod) {
        const f = mod[fname];
        /* c8 ignore else */
        if (f && filterTest(fname)) {
          const repeatEachTest = 1;
          let success = true;
          for (let i = 0; success && i < repeatEachTest; i++) {
            success = await run(modName, fname, f, testnumber, numberOfTests);
          }
          testnumber++;
          /* c8 ignore else */
          if (success) {
            successfulTests++;
          }
        }
      }
    }
    const end = now();
    print('');
    const success = successfulTests === numberOfTests;
    /* c8 ignore start */
    if (success) {
      print(GREEN, BOLD, 'All tests successful!', GREY, UNBOLD, ` in ${humanizeDuration(end - start)}`);
      printImgBase64(nyanCatImage, 50);
    } else {
      const failedTests = numberOfTests - successfulTests;
      print(RED, BOLD, `> ${failedTests} test${failedTests > 1 ? 's' : ''} failed`);
    }
    /* c8 ignore stop */
    return success
  };

  class TestError extends Error {}

  /**
   * @param {string} reason
   * @throws {TestError}
   */
  const fail = reason => {
    print(RED, BOLD, 'X ', UNBOLD, reason);
    throw new TestError('Test Failed')
  };

  class SkipError extends Error {}

  // eslint-disable-next-line
  const nyanCatImage = ' ';

  /**
   * Observable class prototype.
   *
   * @module observable
   */


  /* c8 ignore start */
  /**
   * Handles named events.
   *
   * @deprecated
   * @template N
   */
  class Observable {
    constructor () {
      /**
       * Some desc.
       * @type {Map<N, any>}
       */
      this._observers = create$6();
    }

    /**
     * @param {N} name
     * @param {function} f
     */
    on (name, f) {
      setIfUndefined(this._observers, name, create$5).add(f);
    }

    /**
     * @param {N} name
     * @param {function} f
     */
    once (name, f) {
      /**
       * @param  {...any} args
       */
      const _f = (...args) => {
        this.off(name, _f);
        f(...args);
      };
      this.on(name, _f);
    }

    /**
     * @param {N} name
     * @param {function} f
     */
    off (name, f) {
      const observers = this._observers.get(name);
      if (observers !== undefined) {
        observers.delete(f);
        if (observers.size === 0) {
          this._observers.delete(name);
        }
      }
    }

    /**
     * Emit a named event. All registered event listeners that listen to the
     * specified name will receive the event.
     *
     * @todo This should catch exceptions
     *
     * @param {N} name The event name.
     * @param {Array<any>} args The arguments that are applied to the event listener.
     */
    emit (name, args) {
      // copy all listeners to an array first to make sure that no event is emitted to listeners that are subscribed while the event handler is called.
      return from((this._observers.get(name) || create$6()).values()).forEach(f => f(...args))
    }

    destroy () {
      this._observers = create$6();
    }
  }
  /* c8 ignore end */

  /**
   * Utility module to create and manipulate Iterators.
   *
   * @module iterator
   */


  /**
   * @template T
   * @param {function():IteratorResult<T>} next
   * @return {IterableIterator<T>}
   */
  const createIterator = next => ({
    /**
     * @return {IterableIterator<T>}
     */
    [Symbol.iterator] () {
      return this
    },
    // @ts-ignore
    next
  });

  /**
   * @template T
   * @param {Iterator<T>} iterator
   * @param {function(T):boolean} filter
   */
  const iteratorFilter = (iterator, filter) => createIterator(() => {
    let res;
    do {
      res = iterator.next();
    } while (!res.done && !filter(res.value))
    return res
  });

  /**
   * @template T,M
   * @param {Iterator<T>} iterator
   * @param {function(T):M} fmap
   */
  const iteratorMap = (iterator, fmap) => createIterator(() => {
    const { done, value } = iterator.next();
    return { done, value: done ? undefined : fmap(value) }
  });

  class DeleteItem {
    /**
     * @param {number} clock
     * @param {number} len
     */
    constructor (clock, len) {
      /**
       * @type {number}
       */
      this.clock = clock;
      /**
       * @type {number}
       */
      this.len = len;
    }
  }

  /**
   * We no longer maintain a DeleteStore. DeleteSet is a temporary object that is created when needed.
   * - When created in a transaction, it must only be accessed after sorting, and merging
   *   - This DeleteSet is send to other clients
   * - We do not create a DeleteSet when we send a sync message. The DeleteSet message is created directly from StructStore
   * - We read a DeleteSet as part of a sync/update message. In this case the DeleteSet is already sorted and merged.
   */
  class DeleteSet {
    constructor () {
      /**
       * @type {Map<number,Array<DeleteItem>>}
       */
      this.clients = new Map();
    }
  }

  /**
   * Iterate over all structs that the DeleteSet gc's.
   *
   * @param {Transaction} transaction
   * @param {DeleteSet} ds
   * @param {function(GC|Item):void} f
   *
   * @function
   */
  const iterateDeletedStructs = (transaction, ds, f) =>
    ds.clients.forEach((deletes, clientid) => {
      const structs = /** @type {Array<GC|Item>} */ (transaction.doc.store.clients.get(clientid));
      for (let i = 0; i < deletes.length; i++) {
        const del = deletes[i];
        iterateStructs(transaction, structs, del.clock, del.len, f);
      }
    });

  /**
   * @param {Array<DeleteItem>} dis
   * @param {number} clock
   * @return {number|null}
   *
   * @private
   * @function
   */
  const findIndexDS = (dis, clock) => {
    let left = 0;
    let right = dis.length - 1;
    while (left <= right) {
      const midindex = floor((left + right) / 2);
      const mid = dis[midindex];
      const midclock = mid.clock;
      if (midclock <= clock) {
        if (clock < midclock + mid.len) {
          return midindex
        }
        left = midindex + 1;
      } else {
        right = midindex - 1;
      }
    }
    return null
  };

  /**
   * @param {DeleteSet} ds
   * @param {ID} id
   * @return {boolean}
   *
   * @private
   * @function
   */
  const isDeleted = (ds, id) => {
    const dis = ds.clients.get(id.client);
    return dis !== undefined && findIndexDS(dis, id.clock) !== null
  };

  /**
   * @param {DeleteSet} ds
   *
   * @private
   * @function
   */
  const sortAndMergeDeleteSet = ds => {
    ds.clients.forEach(dels => {
      dels.sort((a, b) => a.clock - b.clock);
      // merge items without filtering or splicing the array
      // i is the current pointer
      // j refers to the current insert position for the pointed item
      // try to merge dels[i] into dels[j-1] or set dels[j]=dels[i]
      let i, j;
      for (i = 1, j = 1; i < dels.length; i++) {
        const left = dels[j - 1];
        const right = dels[i];
        if (left.clock + left.len >= right.clock) {
          left.len = max(left.len, right.clock + right.len - left.clock);
        } else {
          if (j < i) {
            dels[j] = right;
          }
          j++;
        }
      }
      dels.length = j;
    });
  };

  /**
   * @param {DeleteSet} ds
   * @param {number} client
   * @param {number} clock
   * @param {number} length
   *
   * @private
   * @function
   */
  const addToDeleteSet = (ds, client, clock, length) => {
    setIfUndefined(ds.clients, client, () => /** @type {Array<DeleteItem>} */ ([])).push(new DeleteItem(clock, length));
  };

  /**
   * @param {DSEncoderV1 | DSEncoderV2} encoder
   * @param {DeleteSet} ds
   *
   * @private
   * @function
   */
  const writeDeleteSet = (encoder, ds) => {
    writeVarUint(encoder.restEncoder, ds.clients.size);

    // Ensure that the delete set is written in a deterministic order
    from(ds.clients.entries())
      .sort((a, b) => b[0] - a[0])
      .forEach(([client, dsitems]) => {
        encoder.resetDsCurVal();
        writeVarUint(encoder.restEncoder, client);
        const len = dsitems.length;
        writeVarUint(encoder.restEncoder, len);
        for (let i = 0; i < len; i++) {
          const item = dsitems[i];
          encoder.writeDsClock(item.clock);
          encoder.writeDsLen(item.len);
        }
      });
  };

  /**
   * @module Y
   */

  const generateNewClientId = uint32;

  /**
   * @typedef {Object} DocOpts
   * @property {boolean} [DocOpts.gc=true] Disable garbage collection (default: gc=true)
   * @property {function(Item):boolean} [DocOpts.gcFilter] Will be called before an Item is garbage collected. Return false to keep the Item.
   * @property {string} [DocOpts.guid] Define a globally unique identifier for this document
   * @property {string | null} [DocOpts.collectionid] Associate this document with a collection. This only plays a role if your provider has a concept of collection.
   * @property {any} [DocOpts.meta] Any kind of meta information you want to associate with this document. If this is a subdocument, remote peers will store the meta information as well.
   * @property {boolean} [DocOpts.autoLoad] If a subdocument, automatically load document. If this is a subdocument, remote peers will load the document as well automatically.
   * @property {boolean} [DocOpts.shouldLoad] Whether the document should be synced by the provider now. This is toggled to true when you call ydoc.load()
   */

  /**
   * A Yjs instance handles the state of shared data.
   * @extends Observable<string>
   */
  class Doc extends Observable {
    /**
     * @param {DocOpts} opts configuration
     */
    constructor ({ guid = uuidv4(), collectionid = null, gc = true, gcFilter = () => true, meta = null, autoLoad = false, shouldLoad = true } = {}) {
      super();
      this.gc = gc;
      this.gcFilter = gcFilter;
      this.clientID = generateNewClientId();
      this.guid = guid;
      this.collectionid = collectionid;
      /**
       * @type {Map<string, AbstractType<YEvent<any>>>}
       */
      this.share = new Map();
      this.store = new StructStore();
      /**
       * @type {Transaction | null}
       */
      this._transaction = null;
      /**
       * @type {Array<Transaction>}
       */
      this._transactionCleanups = [];
      /**
       * @type {Set<Doc>}
       */
      this.subdocs = new Set();
      /**
       * If this document is a subdocument - a document integrated into another document - then _item is defined.
       * @type {Item?}
       */
      this._item = null;
      this.shouldLoad = shouldLoad;
      this.autoLoad = autoLoad;
      this.meta = meta;
      /**
       * This is set to true when the persistence provider loaded the document from the database or when the `sync` event fires.
       * Note that not all providers implement this feature. Provider authors are encouraged to fire the `load` event when the doc content is loaded from the database.
       *
       * @type {boolean}
       */
      this.isLoaded = false;
      /**
       * This is set to true when the connection provider has successfully synced with a backend.
       * Note that when using peer-to-peer providers this event may not provide very useful.
       * Also note that not all providers implement this feature. Provider authors are encouraged to fire
       * the `sync` event when the doc has been synced (with `true` as a parameter) or if connection is
       * lost (with false as a parameter).
       */
      this.isSynced = false;
      /**
       * Promise that resolves once the document has been loaded from a presistence provider.
       */
      this.whenLoaded = create(resolve => {
        this.on('load', () => {
          this.isLoaded = true;
          resolve(this);
        });
      });
      const provideSyncedPromise = () => create(resolve => {
        /**
         * @param {boolean} isSynced
         */
        const eventHandler = (isSynced) => {
          if (isSynced === undefined || isSynced === true) {
            this.off('sync', eventHandler);
            resolve();
          }
        };
        this.on('sync', eventHandler);
      });
      this.on('sync', isSynced => {
        if (isSynced === false && this.isSynced) {
          this.whenSynced = provideSyncedPromise();
        }
        this.isSynced = isSynced === undefined || isSynced === true;
        if (!this.isLoaded) {
          this.emit('load', []);
        }
      });
      /**
       * Promise that resolves once the document has been synced with a backend.
       * This promise is recreated when the connection is lost.
       * Note the documentation about the `isSynced` property.
       */
      this.whenSynced = provideSyncedPromise();
    }

    /**
     * Notify the parent document that you request to load data into this subdocument (if it is a subdocument).
     *
     * `load()` might be used in the future to request any provider to load the most current data.
     *
     * It is safe to call `load()` multiple times.
     */
    load () {
      const item = this._item;
      if (item !== null && !this.shouldLoad) {
        transact(/** @type {any} */ (item.parent).doc, transaction => {
          transaction.subdocsLoaded.add(this);
        }, null, true);
      }
      this.shouldLoad = true;
    }

    getSubdocs () {
      return this.subdocs
    }

    getSubdocGuids () {
      return new Set(from(this.subdocs).map(doc => doc.guid))
    }

    /**
     * Changes that happen inside of a transaction are bundled. This means that
     * the observer fires _after_ the transaction is finished and that all changes
     * that happened inside of the transaction are sent as one message to the
     * other peers.
     *
     * @template T
     * @param {function(Transaction):T} f The function that should be executed as a transaction
     * @param {any} [origin] Origin of who started the transaction. Will be stored on transaction.origin
     * @return T
     *
     * @public
     */
    transact (f, origin = null) {
      return transact(this, f, origin)
    }

    /**
     * Define a shared data type.
     *
     * Multiple calls of `y.get(name, TypeConstructor)` yield the same result
     * and do not overwrite each other. I.e.
     * `y.define(name, Y.Array) === y.define(name, Y.Array)`
     *
     * After this method is called, the type is also available on `y.share.get(name)`.
     *
     * *Best Practices:*
     * Define all types right after the Yjs instance is created and store them in a separate object.
     * Also use the typed methods `getText(name)`, `getArray(name)`, ..
     *
     * @example
     *   const y = new Y(..)
     *   const appState = {
     *     document: y.getText('document')
     *     comments: y.getArray('comments')
     *   }
     *
     * @param {string} name
     * @param {Function} TypeConstructor The constructor of the type definition. E.g. Y.Text, Y.Array, Y.Map, ...
     * @return {AbstractType<any>} The created type. Constructed with TypeConstructor
     *
     * @public
     */
    get (name, TypeConstructor = AbstractType) {
      const type = setIfUndefined(this.share, name, () => {
        // @ts-ignore
        const t = new TypeConstructor();
        t._integrate(this, null);
        return t
      });
      const Constr = type.constructor;
      if (TypeConstructor !== AbstractType && Constr !== TypeConstructor) {
        if (Constr === AbstractType) {
          // @ts-ignore
          const t = new TypeConstructor();
          t._map = type._map;
          type._map.forEach(/** @param {Item?} n */ n => {
            for (; n !== null; n = n.left) {
              // @ts-ignore
              n.parent = t;
            }
          });
          t._start = type._start;
          for (let n = t._start; n !== null; n = n.right) {
            n.parent = t;
          }
          t._length = type._length;
          this.share.set(name, t);
          t._integrate(this, null);
          return t
        } else {
          throw new Error(`Type with the name ${name} has already been defined with a different constructor`)
        }
      }
      return type
    }

    /**
     * @template T
     * @param {string} [name]
     * @return {YArray<T>}
     *
     * @public
     */
    getArray (name = '') {
      // @ts-ignore
      return this.get(name, YArray)
    }

    /**
     * @param {string} [name]
     * @return {YText}
     *
     * @public
     */
    getText (name = '') {
      // @ts-ignore
      return this.get(name, YText)
    }

    /**
     * @template T
     * @param {string} [name]
     * @return {YMap<T>}
     *
     * @public
     */
    getMap (name = '') {
      // @ts-ignore
      return this.get(name, YMap)
    }

    /**
     * @param {string} [name]
     * @return {YXmlFragment}
     *
     * @public
     */
    getXmlFragment (name = '') {
      // @ts-ignore
      return this.get(name, YXmlFragment)
    }

    /**
     * Converts the entire document into a js object, recursively traversing each yjs type
     * Doesn't log types that have not been defined (using ydoc.getType(..)).
     *
     * @deprecated Do not use this method and rather call toJSON directly on the shared types.
     *
     * @return {Object<string, any>}
     */
    toJSON () {
      /**
       * @type {Object<string, any>}
       */
      const doc = {};

      this.share.forEach((value, key) => {
        doc[key] = value.toJSON();
      });

      return doc
    }

    /**
     * Emit `destroy` event and unregister all event handlers.
     */
    destroy () {
      from(this.subdocs).forEach(subdoc => subdoc.destroy());
      const item = this._item;
      if (item !== null) {
        this._item = null;
        const content = /** @type {ContentDoc} */ (item.content);
        content.doc = new Doc({ guid: this.guid, ...content.opts, shouldLoad: false });
        content.doc._item = item;
        transact(/** @type {any} */ (item).parent.doc, transaction => {
          const doc = content.doc;
          if (!item.deleted) {
            transaction.subdocsAdded.add(doc);
          }
          transaction.subdocsRemoved.add(this);
        }, null, true);
      }
      this.emit('destroyed', [true]);
      this.emit('destroy', [this]);
      super.destroy();
    }

    /**
     * @param {string} eventName
     * @param {function(...any):any} f
     */
    on (eventName, f) {
      super.on(eventName, f);
    }

    /**
     * @param {string} eventName
     * @param {function} f
     */
    off (eventName, f) {
      super.off(eventName, f);
    }
  }

  class DSEncoderV1 {
    constructor () {
      this.restEncoder = createEncoder();
    }

    toUint8Array () {
      return toUint8Array(this.restEncoder)
    }

    resetDsCurVal () {
      // nop
    }

    /**
     * @param {number} clock
     */
    writeDsClock (clock) {
      writeVarUint(this.restEncoder, clock);
    }

    /**
     * @param {number} len
     */
    writeDsLen (len) {
      writeVarUint(this.restEncoder, len);
    }
  }

  class UpdateEncoderV1 extends DSEncoderV1 {
    /**
     * @param {ID} id
     */
    writeLeftID (id) {
      writeVarUint(this.restEncoder, id.client);
      writeVarUint(this.restEncoder, id.clock);
    }

    /**
     * @param {ID} id
     */
    writeRightID (id) {
      writeVarUint(this.restEncoder, id.client);
      writeVarUint(this.restEncoder, id.clock);
    }

    /**
     * Use writeClient and writeClock instead of writeID if possible.
     * @param {number} client
     */
    writeClient (client) {
      writeVarUint(this.restEncoder, client);
    }

    /**
     * @param {number} info An unsigned 8-bit integer
     */
    writeInfo (info) {
      writeUint8(this.restEncoder, info);
    }

    /**
     * @param {string} s
     */
    writeString (s) {
      writeVarString(this.restEncoder, s);
    }

    /**
     * @param {boolean} isYKey
     */
    writeParentInfo (isYKey) {
      writeVarUint(this.restEncoder, isYKey ? 1 : 0);
    }

    /**
     * @param {number} info An unsigned 8-bit integer
     */
    writeTypeRef (info) {
      writeVarUint(this.restEncoder, info);
    }

    /**
     * Write len of a struct - well suited for Opt RLE encoder.
     *
     * @param {number} len
     */
    writeLen (len) {
      writeVarUint(this.restEncoder, len);
    }

    /**
     * @param {any} any
     */
    writeAny (any) {
      writeAny(this.restEncoder, any);
    }

    /**
     * @param {Uint8Array} buf
     */
    writeBuf (buf) {
      writeVarUint8Array(this.restEncoder, buf);
    }

    /**
     * @param {any} embed
     */
    writeJSON (embed) {
      writeVarString(this.restEncoder, JSON.stringify(embed));
    }

    /**
     * @param {string} key
     */
    writeKey (key) {
      writeVarString(this.restEncoder, key);
    }
  }

  class DSEncoderV2 {
    constructor () {
      this.restEncoder = createEncoder(); // encodes all the rest / non-optimized
      this.dsCurrVal = 0;
    }

    toUint8Array () {
      return toUint8Array(this.restEncoder)
    }

    resetDsCurVal () {
      this.dsCurrVal = 0;
    }

    /**
     * @param {number} clock
     */
    writeDsClock (clock) {
      const diff = clock - this.dsCurrVal;
      this.dsCurrVal = clock;
      writeVarUint(this.restEncoder, diff);
    }

    /**
     * @param {number} len
     */
    writeDsLen (len) {
      if (len === 0) {
        unexpectedCase();
      }
      writeVarUint(this.restEncoder, len - 1);
      this.dsCurrVal += len;
    }
  }

  class UpdateEncoderV2 extends DSEncoderV2 {
    constructor () {
      super();
      /**
       * @type {Map<string,number>}
       */
      this.keyMap = new Map();
      /**
       * Refers to the next uniqe key-identifier to me used.
       * See writeKey method for more information.
       *
       * @type {number}
       */
      this.keyClock = 0;
      this.keyClockEncoder = new IntDiffOptRleEncoder();
      this.clientEncoder = new UintOptRleEncoder();
      this.leftClockEncoder = new IntDiffOptRleEncoder();
      this.rightClockEncoder = new IntDiffOptRleEncoder();
      this.infoEncoder = new RleEncoder(writeUint8);
      this.stringEncoder = new StringEncoder();
      this.parentInfoEncoder = new RleEncoder(writeUint8);
      this.typeRefEncoder = new UintOptRleEncoder();
      this.lenEncoder = new UintOptRleEncoder();
    }

    toUint8Array () {
      const encoder = createEncoder();
      writeVarUint(encoder, 0); // this is a feature flag that we might use in the future
      writeVarUint8Array(encoder, this.keyClockEncoder.toUint8Array());
      writeVarUint8Array(encoder, this.clientEncoder.toUint8Array());
      writeVarUint8Array(encoder, this.leftClockEncoder.toUint8Array());
      writeVarUint8Array(encoder, this.rightClockEncoder.toUint8Array());
      writeVarUint8Array(encoder, toUint8Array(this.infoEncoder));
      writeVarUint8Array(encoder, this.stringEncoder.toUint8Array());
      writeVarUint8Array(encoder, toUint8Array(this.parentInfoEncoder));
      writeVarUint8Array(encoder, this.typeRefEncoder.toUint8Array());
      writeVarUint8Array(encoder, this.lenEncoder.toUint8Array());
      // @note The rest encoder is appended! (note the missing var)
      writeUint8Array(encoder, toUint8Array(this.restEncoder));
      return toUint8Array(encoder)
    }

    /**
     * @param {ID} id
     */
    writeLeftID (id) {
      this.clientEncoder.write(id.client);
      this.leftClockEncoder.write(id.clock);
    }

    /**
     * @param {ID} id
     */
    writeRightID (id) {
      this.clientEncoder.write(id.client);
      this.rightClockEncoder.write(id.clock);
    }

    /**
     * @param {number} client
     */
    writeClient (client) {
      this.clientEncoder.write(client);
    }

    /**
     * @param {number} info An unsigned 8-bit integer
     */
    writeInfo (info) {
      this.infoEncoder.write(info);
    }

    /**
     * @param {string} s
     */
    writeString (s) {
      this.stringEncoder.write(s);
    }

    /**
     * @param {boolean} isYKey
     */
    writeParentInfo (isYKey) {
      this.parentInfoEncoder.write(isYKey ? 1 : 0);
    }

    /**
     * @param {number} info An unsigned 8-bit integer
     */
    writeTypeRef (info) {
      this.typeRefEncoder.write(info);
    }

    /**
     * Write len of a struct - well suited for Opt RLE encoder.
     *
     * @param {number} len
     */
    writeLen (len) {
      this.lenEncoder.write(len);
    }

    /**
     * @param {any} any
     */
    writeAny (any) {
      writeAny(this.restEncoder, any);
    }

    /**
     * @param {Uint8Array} buf
     */
    writeBuf (buf) {
      writeVarUint8Array(this.restEncoder, buf);
    }

    /**
     * This is mainly here for legacy purposes.
     *
     * Initial we incoded objects using JSON. Now we use the much faster lib0/any-encoder. This method mainly exists for legacy purposes for the v1 encoder.
     *
     * @param {any} embed
     */
    writeJSON (embed) {
      writeAny(this.restEncoder, embed);
    }

    /**
     * Property keys are often reused. For example, in y-prosemirror the key `bold` might
     * occur very often. For a 3d application, the key `position` might occur very often.
     *
     * We cache these keys in a Map and refer to them via a unique number.
     *
     * @param {string} key
     */
    writeKey (key) {
      const clock = this.keyMap.get(key);
      if (clock === undefined) {
        /**
         * @todo uncomment to introduce this feature finally
         *
         * Background. The ContentFormat object was always encoded using writeKey, but the decoder used to use readString.
         * Furthermore, I forgot to set the keyclock. So everything was working fine.
         *
         * However, this feature here is basically useless as it is not being used (it actually only consumes extra memory).
         *
         * I don't know yet how to reintroduce this feature..
         *
         * Older clients won't be able to read updates when we reintroduce this feature. So this should probably be done using a flag.
         *
         */
        // this.keyMap.set(key, this.keyClock)
        this.keyClockEncoder.write(this.keyClock++);
        this.stringEncoder.write(key);
      } else {
        this.keyClockEncoder.write(clock);
      }
    }
  }

  /**
   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
   * @param {Array<GC|Item>} structs All structs by `client`
   * @param {number} client
   * @param {number} clock write structs starting with `ID(client,clock)`
   *
   * @function
   */
  const writeStructs = (encoder, structs, client, clock) => {
    // write first id
    clock = max(clock, structs[0].id.clock); // make sure the first id exists
    const startNewStructs = findIndexSS(structs, clock);
    // write # encoded structs
    writeVarUint(encoder.restEncoder, structs.length - startNewStructs);
    encoder.writeClient(client);
    writeVarUint(encoder.restEncoder, clock);
    const firstStruct = structs[startNewStructs];
    // write first struct with an offset
    firstStruct.write(encoder, clock - firstStruct.id.clock);
    for (let i = startNewStructs + 1; i < structs.length; i++) {
      structs[i].write(encoder, 0);
    }
  };

  /**
   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
   * @param {StructStore} store
   * @param {Map<number,number>} _sm
   *
   * @private
   * @function
   */
  const writeClientsStructs = (encoder, store, _sm) => {
    // we filter all valid _sm entries into sm
    const sm = new Map();
    _sm.forEach((clock, client) => {
      // only write if new structs are available
      if (getState(store, client) > clock) {
        sm.set(client, clock);
      }
    });
    getStateVector(store).forEach((_clock, client) => {
      if (!_sm.has(client)) {
        sm.set(client, 0);
      }
    });
    // write # states that were updated
    writeVarUint(encoder.restEncoder, sm.size);
    // Write items with higher client ids first
    // This heavily improves the conflict algorithm.
    from(sm.entries()).sort((a, b) => b[0] - a[0]).forEach(([client, clock]) => {
      writeStructs(encoder, /** @type {Array<GC|Item>} */ (store.clients.get(client)), client, clock);
    });
  };

  /**
   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
   * @param {Transaction} transaction
   *
   * @private
   * @function
   */
  const writeStructsFromTransaction = (encoder, transaction) => writeClientsStructs(encoder, transaction.doc.store, transaction.beforeState);

  /**
   * General event handler implementation.
   *
   * @template ARG0, ARG1
   *
   * @private
   */
  class EventHandler {
    constructor () {
      /**
       * @type {Array<function(ARG0, ARG1):void>}
       */
      this.l = [];
    }
  }

  /**
   * @template ARG0,ARG1
   * @returns {EventHandler<ARG0,ARG1>}
   *
   * @private
   * @function
   */
  const createEventHandler = () => new EventHandler();

  /**
   * Adds an event listener that is called when
   * {@link EventHandler#callEventListeners} is called.
   *
   * @template ARG0,ARG1
   * @param {EventHandler<ARG0,ARG1>} eventHandler
   * @param {function(ARG0,ARG1):void} f The event handler.
   *
   * @private
   * @function
   */
  const addEventHandlerListener = (eventHandler, f) =>
    eventHandler.l.push(f);

  /**
   * Removes an event listener.
   *
   * @template ARG0,ARG1
   * @param {EventHandler<ARG0,ARG1>} eventHandler
   * @param {function(ARG0,ARG1):void} f The event handler that was added with
   *                     {@link EventHandler#addEventListener}
   *
   * @private
   * @function
   */
  const removeEventHandlerListener = (eventHandler, f) => {
    const l = eventHandler.l;
    const len = l.length;
    eventHandler.l = l.filter(g => f !== g);
    if (len === eventHandler.l.length) {
      console.error('[yjs] Tried to remove event handler that doesn\'t exist.');
    }
  };

  /**
   * Call all event listeners that were added via
   * {@link EventHandler#addEventListener}.
   *
   * @template ARG0,ARG1
   * @param {EventHandler<ARG0,ARG1>} eventHandler
   * @param {ARG0} arg0
   * @param {ARG1} arg1
   *
   * @private
   * @function
   */
  const callEventHandlerListeners = (eventHandler, arg0, arg1) =>
    callAll(eventHandler.l, [arg0, arg1]);

  class ID {
    /**
     * @param {number} client client id
     * @param {number} clock unique per client id, continuous number
     */
    constructor (client, clock) {
      /**
       * Client id
       * @type {number}
       */
      this.client = client;
      /**
       * unique per client id, continuous number
       * @type {number}
       */
      this.clock = clock;
    }
  }

  /**
   * @param {ID | null} a
   * @param {ID | null} b
   * @return {boolean}
   *
   * @function
   */
  const compareIDs = (a, b) => a === b || (a !== null && b !== null && a.client === b.client && a.clock === b.clock);

  /**
   * @param {number} client
   * @param {number} clock
   *
   * @private
   * @function
   */
  const createID = (client, clock) => new ID(client, clock);

  /**
   * The top types are mapped from y.share.get(keyname) => type.
   * `type` does not store any information about the `keyname`.
   * This function finds the correct `keyname` for `type` and throws otherwise.
   *
   * @param {AbstractType<any>} type
   * @return {string}
   *
   * @private
   * @function
   */
  const findRootTypeKey = type => {
    // @ts-ignore _y must be defined, otherwise unexpected case
    for (const [key, value] of type.doc.share.entries()) {
      if (value === type) {
        return key
      }
    }
    throw unexpectedCase()
  };

  /**
   * @param {Item} item
   * @param {Snapshot|undefined} snapshot
   *
   * @protected
   * @function
   */
  const isVisible = (item, snapshot) => snapshot === undefined
    ? !item.deleted
    : snapshot.sv.has(item.id.client) && (snapshot.sv.get(item.id.client) || 0) > item.id.clock && !isDeleted(snapshot.ds, item.id);

  /**
   * @param {Transaction} transaction
   * @param {Snapshot} snapshot
   */
  const splitSnapshotAffectedStructs = (transaction, snapshot) => {
    const meta = setIfUndefined(transaction.meta, splitSnapshotAffectedStructs, create$5);
    const store = transaction.doc.store;
    // check if we already split for this snapshot
    if (!meta.has(snapshot)) {
      snapshot.sv.forEach((clock, client) => {
        if (clock < getState(store, client)) {
          getItemCleanStart(transaction, createID(client, clock));
        }
      });
      iterateDeletedStructs(transaction, snapshot.ds, _item => {});
      meta.add(snapshot);
    }
  };

  class StructStore {
    constructor () {
      /**
       * @type {Map<number,Array<GC|Item>>}
       */
      this.clients = new Map();
      /**
       * @type {null | { missing: Map<number, number>, update: Uint8Array }}
       */
      this.pendingStructs = null;
      /**
       * @type {null | Uint8Array}
       */
      this.pendingDs = null;
    }
  }

  /**
   * Return the states as a Map<client,clock>.
   * Note that clock refers to the next expected clock id.
   *
   * @param {StructStore} store
   * @return {Map<number,number>}
   *
   * @public
   * @function
   */
  const getStateVector = store => {
    const sm = new Map();
    store.clients.forEach((structs, client) => {
      const struct = structs[structs.length - 1];
      sm.set(client, struct.id.clock + struct.length);
    });
    return sm
  };

  /**
   * @param {StructStore} store
   * @param {number} client
   * @return {number}
   *
   * @public
   * @function
   */
  const getState = (store, client) => {
    const structs = store.clients.get(client);
    if (structs === undefined) {
      return 0
    }
    const lastStruct = structs[structs.length - 1];
    return lastStruct.id.clock + lastStruct.length
  };

  /**
   * @param {StructStore} store
   * @param {GC|Item} struct
   *
   * @private
   * @function
   */
  const addStruct = (store, struct) => {
    let structs = store.clients.get(struct.id.client);
    if (structs === undefined) {
      structs = [];
      store.clients.set(struct.id.client, structs);
    } else {
      const lastStruct = structs[structs.length - 1];
      if (lastStruct.id.clock + lastStruct.length !== struct.id.clock) {
        throw unexpectedCase()
      }
    }
    structs.push(struct);
  };

  /**
   * Perform a binary search on a sorted array
   * @param {Array<Item|GC>} structs
   * @param {number} clock
   * @return {number}
   *
   * @private
   * @function
   */
  const findIndexSS = (structs, clock) => {
    let left = 0;
    let right = structs.length - 1;
    let mid = structs[right];
    let midclock = mid.id.clock;
    if (midclock === clock) {
      return right
    }
    // @todo does it even make sense to pivot the search?
    // If a good split misses, it might actually increase the time to find the correct item.
    // Currently, the only advantage is that search with pivoting might find the item on the first try.
    let midindex = floor((clock / (midclock + mid.length - 1)) * right); // pivoting the search
    while (left <= right) {
      mid = structs[midindex];
      midclock = mid.id.clock;
      if (midclock <= clock) {
        if (clock < midclock + mid.length) {
          return midindex
        }
        left = midindex + 1;
      } else {
        right = midindex - 1;
      }
      midindex = floor((left + right) / 2);
    }
    // Always check state before looking for a struct in StructStore
    // Therefore the case of not finding a struct is unexpected
    throw unexpectedCase()
  };

  /**
   * Expects that id is actually in store. This function throws or is an infinite loop otherwise.
   *
   * @param {StructStore} store
   * @param {ID} id
   * @return {GC|Item}
   *
   * @private
   * @function
   */
  const find = (store, id) => {
    /**
     * @type {Array<GC|Item>}
     */
    // @ts-ignore
    const structs = store.clients.get(id.client);
    return structs[findIndexSS(structs, id.clock)]
  };

  /**
   * Expects that id is actually in store. This function throws or is an infinite loop otherwise.
   * @private
   * @function
   */
  const getItem = /** @type {function(StructStore,ID):Item} */ (find);

  /**
   * @param {Transaction} transaction
   * @param {Array<Item|GC>} structs
   * @param {number} clock
   */
  const findIndexCleanStart = (transaction, structs, clock) => {
    const index = findIndexSS(structs, clock);
    const struct = structs[index];
    if (struct.id.clock < clock && struct instanceof Item) {
      structs.splice(index + 1, 0, splitItem(transaction, struct, clock - struct.id.clock));
      return index + 1
    }
    return index
  };

  /**
   * Expects that id is actually in store. This function throws or is an infinite loop otherwise.
   *
   * @param {Transaction} transaction
   * @param {ID} id
   * @return {Item}
   *
   * @private
   * @function
   */
  const getItemCleanStart = (transaction, id) => {
    const structs = /** @type {Array<Item>} */ (transaction.doc.store.clients.get(id.client));
    return structs[findIndexCleanStart(transaction, structs, id.clock)]
  };

  /**
   * Expects that id is actually in store. This function throws or is an infinite loop otherwise.
   *
   * @param {Transaction} transaction
   * @param {StructStore} store
   * @param {ID} id
   * @return {Item}
   *
   * @private
   * @function
   */
  const getItemCleanEnd = (transaction, store, id) => {
    /**
     * @type {Array<Item>}
     */
    // @ts-ignore
    const structs = store.clients.get(id.client);
    const index = findIndexSS(structs, id.clock);
    const struct = structs[index];
    if (id.clock !== struct.id.clock + struct.length - 1 && struct.constructor !== GC) {
      structs.splice(index + 1, 0, splitItem(transaction, struct, id.clock - struct.id.clock + 1));
    }
    return struct
  };

  /**
   * Replace `item` with `newitem` in store
   * @param {StructStore} store
   * @param {GC|Item} struct
   * @param {GC|Item} newStruct
   *
   * @private
   * @function
   */
  const replaceStruct = (store, struct, newStruct) => {
    const structs = /** @type {Array<GC|Item>} */ (store.clients.get(struct.id.client));
    structs[findIndexSS(structs, struct.id.clock)] = newStruct;
  };

  /**
   * Iterate over a range of structs
   *
   * @param {Transaction} transaction
   * @param {Array<Item|GC>} structs
   * @param {number} clockStart Inclusive start
   * @param {number} len
   * @param {function(GC|Item):void} f
   *
   * @function
   */
  const iterateStructs = (transaction, structs, clockStart, len, f) => {
    if (len === 0) {
      return
    }
    const clockEnd = clockStart + len;
    let index = findIndexCleanStart(transaction, structs, clockStart);
    let struct;
    do {
      struct = structs[index++];
      if (clockEnd < struct.id.clock + struct.length) {
        findIndexCleanStart(transaction, structs, clockEnd);
      }
      f(struct);
    } while (index < structs.length && structs[index].id.clock < clockEnd)
  };

  /**
   * A transaction is created for every change on the Yjs model. It is possible
   * to bundle changes on the Yjs model in a single transaction to
   * minimize the number on messages sent and the number of observer calls.
   * If possible the user of this library should bundle as many changes as
   * possible. Here is an example to illustrate the advantages of bundling:
   *
   * @example
   * const map = y.define('map', YMap)
   * // Log content when change is triggered
   * map.observe(() => {
   *   console.log('change triggered')
   * })
   * // Each change on the map type triggers a log message:
   * map.set('a', 0) // => "change triggered"
   * map.set('b', 0) // => "change triggered"
   * // When put in a transaction, it will trigger the log after the transaction:
   * y.transact(() => {
   *   map.set('a', 1)
   *   map.set('b', 1)
   * }) // => "change triggered"
   *
   * @public
   */
  class Transaction {
    /**
     * @param {Doc} doc
     * @param {any} origin
     * @param {boolean} local
     */
    constructor (doc, origin, local) {
      /**
       * The Yjs instance.
       * @type {Doc}
       */
      this.doc = doc;
      /**
       * Describes the set of deleted items by ids
       * @type {DeleteSet}
       */
      this.deleteSet = new DeleteSet();
      /**
       * Holds the state before the transaction started.
       * @type {Map<Number,Number>}
       */
      this.beforeState = getStateVector(doc.store);
      /**
       * Holds the state after the transaction.
       * @type {Map<Number,Number>}
       */
      this.afterState = new Map();
      /**
       * All types that were directly modified (property added or child
       * inserted/deleted). New types are not included in this Set.
       * Maps from type to parentSubs (`item.parentSub = null` for YArray)
       * @type {Map<AbstractType<YEvent<any>>,Set<String|null>>}
       */
      this.changed = new Map();
      /**
       * Stores the events for the types that observe also child elements.
       * It is mainly used by `observeDeep`.
       * @type {Map<AbstractType<YEvent<any>>,Array<YEvent<any>>>}
       */
      this.changedParentTypes = new Map();
      /**
       * @type {Array<AbstractStruct>}
       */
      this._mergeStructs = [];
      /**
       * @type {any}
       */
      this.origin = origin;
      /**
       * Stores meta information on the transaction
       * @type {Map<any,any>}
       */
      this.meta = new Map();
      /**
       * Whether this change originates from this doc.
       * @type {boolean}
       */
      this.local = local;
      /**
       * @type {Set<Doc>}
       */
      this.subdocsAdded = new Set();
      /**
       * @type {Set<Doc>}
       */
      this.subdocsRemoved = new Set();
      /**
       * @type {Set<Doc>}
       */
      this.subdocsLoaded = new Set();
      /**
       * @type {boolean}
       */
      this._needFormattingCleanup = false;
    }
  }

  /**
   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
   * @param {Transaction} transaction
   * @return {boolean} Whether data was written.
   */
  const writeUpdateMessageFromTransaction = (encoder, transaction) => {
    if (transaction.deleteSet.clients.size === 0 && !any(transaction.afterState, (clock, client) => transaction.beforeState.get(client) !== clock)) {
      return false
    }
    sortAndMergeDeleteSet(transaction.deleteSet);
    writeStructsFromTransaction(encoder, transaction);
    writeDeleteSet(encoder, transaction.deleteSet);
    return true
  };

  /**
   * If `type.parent` was added in current transaction, `type` technically
   * did not change, it was just added and we should not fire events for `type`.
   *
   * @param {Transaction} transaction
   * @param {AbstractType<YEvent<any>>} type
   * @param {string|null} parentSub
   */
  const addChangedTypeToTransaction = (transaction, type, parentSub) => {
    const item = type._item;
    if (item === null || (item.id.clock < (transaction.beforeState.get(item.id.client) || 0) && !item.deleted)) {
      setIfUndefined(transaction.changed, type, create$5).add(parentSub);
    }
  };

  /**
   * @param {Array<AbstractStruct>} structs
   * @param {number} pos
   * @return {number} # of merged structs
   */
  const tryToMergeWithLefts = (structs, pos) => {
    let right = structs[pos];
    let left = structs[pos - 1];
    let i = pos;
    for (; i > 0; right = left, left = structs[--i - 1]) {
      if (left.deleted === right.deleted && left.constructor === right.constructor) {
        if (left.mergeWith(right)) {
          if (right instanceof Item && right.parentSub !== null && /** @type {AbstractType<any>} */ (right.parent)._map.get(right.parentSub) === right) {
            /** @type {AbstractType<any>} */ (right.parent)._map.set(right.parentSub, /** @type {Item} */ (left));
          }
          continue
        }
      }
      break
    }
    const merged = pos - i;
    if (merged) {
      // remove all merged structs from the array
      structs.splice(pos + 1 - merged, merged);
    }
    return merged
  };

  /**
   * @param {DeleteSet} ds
   * @param {StructStore} store
   * @param {function(Item):boolean} gcFilter
   */
  const tryGcDeleteSet = (ds, store, gcFilter) => {
    for (const [client, deleteItems] of ds.clients.entries()) {
      const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client));
      for (let di = deleteItems.length - 1; di >= 0; di--) {
        const deleteItem = deleteItems[di];
        const endDeleteItemClock = deleteItem.clock + deleteItem.len;
        for (
          let si = findIndexSS(structs, deleteItem.clock), struct = structs[si];
          si < structs.length && struct.id.clock < endDeleteItemClock;
          struct = structs[++si]
        ) {
          const struct = structs[si];
          if (deleteItem.clock + deleteItem.len <= struct.id.clock) {
            break
          }
          if (struct instanceof Item && struct.deleted && !struct.keep && gcFilter(struct)) {
            struct.gc(store, false);
          }
        }
      }
    }
  };

  /**
   * @param {DeleteSet} ds
   * @param {StructStore} store
   */
  const tryMergeDeleteSet = (ds, store) => {
    // try to merge deleted / gc'd items
    // merge from right to left for better efficiecy and so we don't miss any merge targets
    ds.clients.forEach((deleteItems, client) => {
      const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client));
      for (let di = deleteItems.length - 1; di >= 0; di--) {
        const deleteItem = deleteItems[di];
        // start with merging the item next to the last deleted item
        const mostRightIndexToCheck = min(structs.length - 1, 1 + findIndexSS(structs, deleteItem.clock + deleteItem.len - 1));
        for (
          let si = mostRightIndexToCheck, struct = structs[si];
          si > 0 && struct.id.clock >= deleteItem.clock;
          struct = structs[si]
        ) {
          si -= 1 + tryToMergeWithLefts(structs, si);
        }
      }
    });
  };

  /**
   * @param {Array<Transaction>} transactionCleanups
   * @param {number} i
   */
  const cleanupTransactions = (transactionCleanups, i) => {
    if (i < transactionCleanups.length) {
      const transaction = transactionCleanups[i];
      const doc = transaction.doc;
      const store = doc.store;
      const ds = transaction.deleteSet;
      const mergeStructs = transaction._mergeStructs;
      try {
        sortAndMergeDeleteSet(ds);
        transaction.afterState = getStateVector(transaction.doc.store);
        doc.emit('beforeObserverCalls', [transaction, doc]);
        /**
         * An array of event callbacks.
         *
         * Each callback is called even if the other ones throw errors.
         *
         * @type {Array<function():void>}
         */
        const fs = [];
        // observe events on changed types
        transaction.changed.forEach((subs, itemtype) =>
          fs.push(() => {
            if (itemtype._item === null || !itemtype._item.deleted) {
              itemtype._callObserver(transaction, subs);
            }
          })
        );
        fs.push(() => {
          // deep observe events
          transaction.changedParentTypes.forEach((events, type) => {
            // We need to think about the possibility that the user transforms the
            // Y.Doc in the event.
            if (type._dEH.l.length > 0 && (type._item === null || !type._item.deleted)) {
              events = events
                .filter(event =>
                  event.target._item === null || !event.target._item.deleted
                );
              events
                .forEach(event => {
                  event.currentTarget = type;
                  // path is relative to the current target
                  event._path = null;
                });
              // sort events by path length so that top-level events are fired first.
              events
                .sort((event1, event2) => event1.path.length - event2.path.length);
              // We don't need to check for events.length
              // because we know it has at least one element
              callEventHandlerListeners(type._dEH, events, transaction);
            }
          });
        });
        fs.push(() => doc.emit('afterTransaction', [transaction, doc]));
        callAll(fs, []);
        if (transaction._needFormattingCleanup) {
          cleanupYTextAfterTransaction(transaction);
        }
      } finally {
        // Replace deleted items with ItemDeleted / GC.
        // This is where content is actually remove from the Yjs Doc.
        if (doc.gc) {
          tryGcDeleteSet(ds, store, doc.gcFilter);
        }
        tryMergeDeleteSet(ds, store);

        // on all affected store.clients props, try to merge
        transaction.afterState.forEach((clock, client) => {
          const beforeClock = transaction.beforeState.get(client) || 0;
          if (beforeClock !== clock) {
            const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client));
            // we iterate from right to left so we can safely remove entries
            const firstChangePos = max(findIndexSS(structs, beforeClock), 1);
            for (let i = structs.length - 1; i >= firstChangePos;) {
              i -= 1 + tryToMergeWithLefts(structs, i);
            }
          }
        });
        // try to merge mergeStructs
        // @todo: it makes more sense to transform mergeStructs to a DS, sort it, and merge from right to left
        //        but at the moment DS does not handle duplicates
        for (let i = mergeStructs.length - 1; i >= 0; i--) {
          const { client, clock } = mergeStructs[i].id;
          const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client));
          const replacedStructPos = findIndexSS(structs, clock);
          if (replacedStructPos + 1 < structs.length) {
            if (tryToMergeWithLefts(structs, replacedStructPos + 1) > 1) {
              continue // no need to perform next check, both are already merged
            }
          }
          if (replacedStructPos > 0) {
            tryToMergeWithLefts(structs, replacedStructPos);
          }
        }
        if (!transaction.local && transaction.afterState.get(doc.clientID) !== transaction.beforeState.get(doc.clientID)) {
          print(ORANGE, BOLD, '[yjs] ', UNBOLD, RED, 'Changed the client-id because another client seems to be using it.');
          doc.clientID = generateNewClientId();
        }
        // @todo Merge all the transactions into one and provide send the data as a single update message
        doc.emit('afterTransactionCleanup', [transaction, doc]);
        if (doc._observers.has('update')) {
          const encoder = new UpdateEncoderV1();
          const hasContent = writeUpdateMessageFromTransaction(encoder, transaction);
          if (hasContent) {
            doc.emit('update', [encoder.toUint8Array(), transaction.origin, doc, transaction]);
          }
        }
        if (doc._observers.has('updateV2')) {
          const encoder = new UpdateEncoderV2();
          const hasContent = writeUpdateMessageFromTransaction(encoder, transaction);
          if (hasContent) {
            doc.emit('updateV2', [encoder.toUint8Array(), transaction.origin, doc, transaction]);
          }
        }
        const { subdocsAdded, subdocsLoaded, subdocsRemoved } = transaction;
        if (subdocsAdded.size > 0 || subdocsRemoved.size > 0 || subdocsLoaded.size > 0) {
          subdocsAdded.forEach(subdoc => {
            subdoc.clientID = doc.clientID;
            if (subdoc.collectionid == null) {
              subdoc.collectionid = doc.collectionid;
            }
            doc.subdocs.add(subdoc);
          });
          subdocsRemoved.forEach(subdoc => doc.subdocs.delete(subdoc));
          doc.emit('subdocs', [{ loaded: subdocsLoaded, added: subdocsAdded, removed: subdocsRemoved }, doc, transaction]);
          subdocsRemoved.forEach(subdoc => subdoc.destroy());
        }

        if (transactionCleanups.length <= i + 1) {
          doc._transactionCleanups = [];
          doc.emit('afterAllTransactions', [doc, transactionCleanups]);
        } else {
          cleanupTransactions(transactionCleanups, i + 1);
        }
      }
    }
  };

  /**
   * Implements the functionality of `y.transact(()=>{..})`
   *
   * @template T
   * @param {Doc} doc
   * @param {function(Transaction):T} f
   * @param {any} [origin=true]
   * @return {T}
   *
   * @function
   */
  const transact = (doc, f, origin = null, local = true) => {
    const transactionCleanups = doc._transactionCleanups;
    let initialCall = false;
    /**
     * @type {any}
     */
    let result = null;
    if (doc._transaction === null) {
      initialCall = true;
      doc._transaction = new Transaction(doc, origin, local);
      transactionCleanups.push(doc._transaction);
      if (transactionCleanups.length === 1) {
        doc.emit('beforeAllTransactions', [doc]);
      }
      doc.emit('beforeTransaction', [doc._transaction, doc]);
    }
    try {
      result = f(doc._transaction);
    } finally {
      if (initialCall) {
        const finishCleanup = doc._transaction === transactionCleanups[0];
        doc._transaction = null;
        if (finishCleanup) {
          // The first transaction ended, now process observer calls.
          // Observer call may create new transactions for which we need to call the observers and do cleanup.
          // We don't want to nest these calls, so we execute these calls one after
          // another.
          // Also we need to ensure that all cleanups are called, even if the
          // observes throw errors.
          // This file is full of hacky try {} finally {} blocks to ensure that an
          // event can throw errors and also that the cleanup is called.
          cleanupTransactions(transactionCleanups, 0);
        }
      }
    }
    return result
  };

  const errorComputeChanges = 'You must not compute changes after the event-handler fired.';

  /**
   * @template {AbstractType<any>} T
   * YEvent describes the changes on a YType.
   */
  class YEvent {
    /**
     * @param {T} target The changed type.
     * @param {Transaction} transaction
     */
    constructor (target, transaction) {
      /**
       * The type on which this event was created on.
       * @type {T}
       */
      this.target = target;
      /**
       * The current target on which the observe callback is called.
       * @type {AbstractType<any>}
       */
      this.currentTarget = target;
      /**
       * The transaction that triggered this event.
       * @type {Transaction}
       */
      this.transaction = transaction;
      /**
       * @type {Object|null}
       */
      this._changes = null;
      /**
       * @type {null | Map<string, { action: 'add' | 'update' | 'delete', oldValue: any, newValue: any }>}
       */
      this._keys = null;
      /**
       * @type {null | Array<{ insert?: string | Array<any> | object | AbstractType<any>, retain?: number, delete?: number, attributes?: Object<string, any> }>}
       */
      this._delta = null;
      /**
       * @type {Array<string|number>|null}
       */
      this._path = null;
    }

    /**
     * Computes the path from `y` to the changed type.
     *
     * @todo v14 should standardize on path: Array<{parent, index}> because that is easier to work with.
     *
     * The following property holds:
     * @example
     *   let type = y
     *   event.path.forEach(dir => {
     *     type = type.get(dir)
     *   })
     *   type === event.target // => true
     */
    get path () {
      return this._path || (this._path = getPathTo(this.currentTarget, this.target))
    }

    /**
     * Check if a struct is deleted by this event.
     *
     * In contrast to change.deleted, this method also returns true if the struct was added and then deleted.
     *
     * @param {AbstractStruct} struct
     * @return {boolean}
     */
    deletes (struct) {
      return isDeleted(this.transaction.deleteSet, struct.id)
    }

    /**
     * @type {Map<string, { action: 'add' | 'update' | 'delete', oldValue: any, newValue: any }>}
     */
    get keys () {
      if (this._keys === null) {
        if (this.transaction.doc._transactionCleanups.length === 0) {
          throw create$2(errorComputeChanges)
        }
        const keys = new Map();
        const target = this.target;
        const changed = /** @type Set<string|null> */ (this.transaction.changed.get(target));
        changed.forEach(key => {
          if (key !== null) {
            const item = /** @type {Item} */ (target._map.get(key));
            /**
             * @type {'delete' | 'add' | 'update'}
             */
            let action;
            let oldValue;
            if (this.adds(item)) {
              let prev = item.left;
              while (prev !== null && this.adds(prev)) {
                prev = prev.left;
              }
              if (this.deletes(item)) {
                if (prev !== null && this.deletes(prev)) {
                  action = 'delete';
                  oldValue = last(prev.content.getContent());
                } else {
                  return
                }
              } else {
                if (prev !== null && this.deletes(prev)) {
                  action = 'update';
                  oldValue = last(prev.content.getContent());
                } else {
                  action = 'add';
                  oldValue = undefined;
                }
              }
            } else {
              if (this.deletes(item)) {
                action = 'delete';
                oldValue = last(/** @type {Item} */ item.content.getContent());
              } else {
                return // nop
              }
            }
            keys.set(key, { action, oldValue });
          }
        });
        this._keys = keys;
      }
      return this._keys
    }

    /**
     * This is a computed property. Note that this can only be safely computed during the
     * event call. Computing this property after other changes happened might result in
     * unexpected behavior (incorrect computation of deltas). A safe way to collect changes
     * is to store the `changes` or the `delta` object. Avoid storing the `transaction` object.
     *
     * @type {Array<{insert?: string | Array<any> | object | AbstractType<any>, retain?: number, delete?: number, attributes?: Object<string, any>}>}
     */
    get delta () {
      return this.changes.delta
    }

    /**
     * Check if a struct is added by this event.
     *
     * In contrast to change.deleted, this method also returns true if the struct was added and then deleted.
     *
     * @param {AbstractStruct} struct
     * @return {boolean}
     */
    adds (struct) {
      return struct.id.clock >= (this.transaction.beforeState.get(struct.id.client) || 0)
    }

    /**
     * This is a computed property. Note that this can only be safely computed during the
     * event call. Computing this property after other changes happened might result in
     * unexpected behavior (incorrect computation of deltas). A safe way to collect changes
     * is to store the `changes` or the `delta` object. Avoid storing the `transaction` object.
     *
     * @type {{added:Set<Item>,deleted:Set<Item>,keys:Map<string,{action:'add'|'update'|'delete',oldValue:any}>,delta:Array<{insert?:Array<any>|string, delete?:number, retain?:number}>}}
     */
    get changes () {
      let changes = this._changes;
      if (changes === null) {
        if (this.transaction.doc._transactionCleanups.length === 0) {
          throw create$2(errorComputeChanges)
        }
        const target = this.target;
        const added = create$5();
        const deleted = create$5();
        /**
         * @type {Array<{insert:Array<any>}|{delete:number}|{retain:number}>}
         */
        const delta = [];
        changes = {
          added,
          deleted,
          delta,
          keys: this.keys
        };
        const changed = /** @type Set<string|null> */ (this.transaction.changed.get(target));
        if (changed.has(null)) {
          /**
           * @type {any}
           */
          let lastOp = null;
          const packOp = () => {
            if (lastOp) {
              delta.push(lastOp);
            }
          };
          for (let item = target._start; item !== null; item = item.right) {
            if (item.deleted) {
              if (this.deletes(item) && !this.adds(item)) {
                if (lastOp === null || lastOp.delete === undefined) {
                  packOp();
                  lastOp = { delete: 0 };
                }
                lastOp.delete += item.length;
                deleted.add(item);
              } // else nop
            } else {
              if (this.adds(item)) {
                if (lastOp === null || lastOp.insert === undefined) {
                  packOp();
                  lastOp = { insert: [] };
                }
                lastOp.insert = lastOp.insert.concat(item.content.getContent());
                added.add(item);
              } else {
                if (lastOp === null || lastOp.retain === undefined) {
                  packOp();
                  lastOp = { retain: 0 };
                }
                lastOp.retain += item.length;
              }
            }
          }
          if (lastOp !== null && lastOp.retain === undefined) {
            packOp();
          }
        }
        this._changes = changes;
      }
      return /** @type {any} */ (changes)
    }
  }

  /**
   * Compute the path from this type to the specified target.
   *
   * @example
   *   // `child` should be accessible via `type.get(path[0]).get(path[1])..`
   *   const path = type.getPathTo(child)
   *   // assuming `type instanceof YArray`
   *   console.log(path) // might look like => [2, 'key1']
   *   child === type.get(path[0]).get(path[1])
   *
   * @param {AbstractType<any>} parent
   * @param {AbstractType<any>} child target
   * @return {Array<string|number>} Path to the target
   *
   * @private
   * @function
   */
  const getPathTo = (parent, child) => {
    const path = [];
    while (child._item !== null && child !== parent) {
      if (child._item.parentSub !== null) {
        // parent is map-ish
        path.unshift(child._item.parentSub);
      } else {
        // parent is array-ish
        let i = 0;
        let c = /** @type {AbstractType<any>} */ (child._item.parent)._start;
        while (c !== child._item && c !== null) {
          if (!c.deleted) {
            i++;
          }
          c = c.right;
        }
        path.unshift(i);
      }
      child = /** @type {AbstractType<any>} */ (child._item.parent);
    }
    return path
  };

  const maxSearchMarker = 80;

  /**
   * A unique timestamp that identifies each marker.
   *
   * Time is relative,.. this is more like an ever-increasing clock.
   *
   * @type {number}
   */
  let globalSearchMarkerTimestamp = 0;

  class ArraySearchMarker {
    /**
     * @param {Item} p
     * @param {number} index
     */
    constructor (p, index) {
      p.marker = true;
      this.p = p;
      this.index = index;
      this.timestamp = globalSearchMarkerTimestamp++;
    }
  }

  /**
   * @param {ArraySearchMarker} marker
   */
  const refreshMarkerTimestamp = marker => { marker.timestamp = globalSearchMarkerTimestamp++; };

  /**
   * This is rather complex so this function is the only thing that should overwrite a marker
   *
   * @param {ArraySearchMarker} marker
   * @param {Item} p
   * @param {number} index
   */
  const overwriteMarker = (marker, p, index) => {
    marker.p.marker = false;
    marker.p = p;
    p.marker = true;
    marker.index = index;
    marker.timestamp = globalSearchMarkerTimestamp++;
  };

  /**
   * @param {Array<ArraySearchMarker>} searchMarker
   * @param {Item} p
   * @param {number} index
   */
  const markPosition = (searchMarker, p, index) => {
    if (searchMarker.length >= maxSearchMarker) {
      // override oldest marker (we don't want to create more objects)
      const marker = searchMarker.reduce((a, b) => a.timestamp < b.timestamp ? a : b);
      overwriteMarker(marker, p, index);
      return marker
    } else {
      // create new marker
      const pm = new ArraySearchMarker(p, index);
      searchMarker.push(pm);
      return pm
    }
  };

  /**
   * Search marker help us to find positions in the associative array faster.
   *
   * They speed up the process of finding a position without much bookkeeping.
   *
   * A maximum of `maxSearchMarker` objects are created.
   *
   * This function always returns a refreshed marker (updated timestamp)
   *
   * @param {AbstractType<any>} yarray
   * @param {number} index
   */
  const findMarker = (yarray, index) => {
    if (yarray._start === null || index === 0 || yarray._searchMarker === null) {
      return null
    }
    const marker = yarray._searchMarker.length === 0 ? null : yarray._searchMarker.reduce((a, b) => abs(index - a.index) < abs(index - b.index) ? a : b);
    let p = yarray._start;
    let pindex = 0;
    if (marker !== null) {
      p = marker.p;
      pindex = marker.index;
      refreshMarkerTimestamp(marker); // we used it, we might need to use it again
    }
    // iterate to right if possible
    while (p.right !== null && pindex < index) {
      if (!p.deleted && p.countable) {
        if (index < pindex + p.length) {
          break
        }
        pindex += p.length;
      }
      p = p.right;
    }
    // iterate to left if necessary (might be that pindex > index)
    while (p.left !== null && pindex > index) {
      p = p.left;
      if (!p.deleted && p.countable) {
        pindex -= p.length;
      }
    }
    // we want to make sure that p can't be merged with left, because that would screw up everything
    // in that cas just return what we have (it is most likely the best marker anyway)
    // iterate to left until p can't be merged with left
    while (p.left !== null && p.left.id.client === p.id.client && p.left.id.clock + p.left.length === p.id.clock) {
      p = p.left;
      if (!p.deleted && p.countable) {
        pindex -= p.length;
      }
    }

    // @todo remove!
    // assure position
    // {
    //   let start = yarray._start
    //   let pos = 0
    //   while (start !== p) {
    //     if (!start.deleted && start.countable) {
    //       pos += start.length
    //     }
    //     start = /** @type {Item} */ (start.right)
    //   }
    //   if (pos !== pindex) {
    //     debugger
    //     throw new Error('Gotcha position fail!')
    //   }
    // }
    // if (marker) {
    //   if (window.lengthes == null) {
    //     window.lengthes = []
    //     window.getLengthes = () => window.lengthes.sort((a, b) => a - b)
    //   }
    //   window.lengthes.push(marker.index - pindex)
    //   console.log('distance', marker.index - pindex, 'len', p && p.parent.length)
    // }
    if (marker !== null && abs(marker.index - pindex) < /** @type {YText|YArray<any>} */ (p.parent).length / maxSearchMarker) {
      // adjust existing marker
      overwriteMarker(marker, p, pindex);
      return marker
    } else {
      // create new marker
      return markPosition(yarray._searchMarker, p, pindex)
    }
  };

  /**
   * Update markers when a change happened.
   *
   * This should be called before doing a deletion!
   *
   * @param {Array<ArraySearchMarker>} searchMarker
   * @param {number} index
   * @param {number} len If insertion, len is positive. If deletion, len is negative.
   */
  const updateMarkerChanges = (searchMarker, index, len) => {
    for (let i = searchMarker.length - 1; i >= 0; i--) {
      const m = searchMarker[i];
      if (len > 0) {
        /**
         * @type {Item|null}
         */
        let p = m.p;
        p.marker = false;
        // Ideally we just want to do a simple position comparison, but this will only work if
        // search markers don't point to deleted items for formats.
        // Iterate marker to prev undeleted countable position so we know what to do when updating a position
        while (p && (p.deleted || !p.countable)) {
          p = p.left;
          if (p && !p.deleted && p.countable) {
            // adjust position. the loop should break now
            m.index -= p.length;
          }
        }
        if (p === null || p.marker === true) {
          // remove search marker if updated position is null or if position is already marked
          searchMarker.splice(i, 1);
          continue
        }
        m.p = p;
        p.marker = true;
      }
      if (index < m.index || (len > 0 && index === m.index)) { // a simple index <= m.index check would actually suffice
        m.index = max(index, m.index + len);
      }
    }
  };

  /**
   * Call event listeners with an event. This will also add an event to all
   * parents (for `.observeDeep` handlers).
   *
   * @template EventType
   * @param {AbstractType<EventType>} type
   * @param {Transaction} transaction
   * @param {EventType} event
   */
  const callTypeObservers = (type, transaction, event) => {
    const changedType = type;
    const changedParentTypes = transaction.changedParentTypes;
    while (true) {
      // @ts-ignore
      setIfUndefined(changedParentTypes, type, () => []).push(event);
      if (type._item === null) {
        break
      }
      type = /** @type {AbstractType<any>} */ (type._item.parent);
    }
    callEventHandlerListeners(changedType._eH, event, transaction);
  };

  /**
   * @template EventType
   * Abstract Yjs Type class
   */
  class AbstractType {
    constructor () {
      /**
       * @type {Item|null}
       */
      this._item = null;
      /**
       * @type {Map<string,Item>}
       */
      this._map = new Map();
      /**
       * @type {Item|null}
       */
      this._start = null;
      /**
       * @type {Doc|null}
       */
      this.doc = null;
      this._length = 0;
      /**
       * Event handlers
       * @type {EventHandler<EventType,Transaction>}
       */
      this._eH = createEventHandler();
      /**
       * Deep event handlers
       * @type {EventHandler<Array<YEvent<any>>,Transaction>}
       */
      this._dEH = createEventHandler();
      /**
       * @type {null | Array<ArraySearchMarker>}
       */
      this._searchMarker = null;
    }

    /**
     * @return {AbstractType<any>|null}
     */
    get parent () {
      return this._item ? /** @type {AbstractType<any>} */ (this._item.parent) : null
    }

    /**
     * Integrate this type into the Yjs instance.
     *
     * * Save this struct in the os
     * * This type is sent to other client
     * * Observer functions are fired
     *
     * @param {Doc} y The Yjs instance
     * @param {Item|null} item
     */
    _integrate (y, item) {
      this.doc = y;
      this._item = item;
    }

    /**
     * @return {AbstractType<EventType>}
     */
    _copy () {
      throw methodUnimplemented()
    }

    /**
     * @return {AbstractType<EventType>}
     */
    clone () {
      throw methodUnimplemented()
    }

    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} _encoder
     */
    _write (_encoder) { }

    /**
     * The first non-deleted item
     */
    get _first () {
      let n = this._start;
      while (n !== null && n.deleted) {
        n = n.right;
      }
      return n
    }

    /**
     * Creates YEvent and calls all type observers.
     * Must be implemented by each type.
     *
     * @param {Transaction} transaction
     * @param {Set<null|string>} _parentSubs Keys changed on this type. `null` if list was modified.
     */
    _callObserver (transaction, _parentSubs) {
      if (!transaction.local && this._searchMarker) {
        this._searchMarker.length = 0;
      }
    }

    /**
     * Observe all events that are created on this type.
     *
     * @param {function(EventType, Transaction):void} f Observer function
     */
    observe (f) {
      addEventHandlerListener(this._eH, f);
    }

    /**
     * Observe all events that are created by this type and its children.
     *
     * @param {function(Array<YEvent<any>>,Transaction):void} f Observer function
     */
    observeDeep (f) {
      addEventHandlerListener(this._dEH, f);
    }

    /**
     * Unregister an observer function.
     *
     * @param {function(EventType,Transaction):void} f Observer function
     */
    unobserve (f) {
      removeEventHandlerListener(this._eH, f);
    }

    /**
     * Unregister an observer function.
     *
     * @param {function(Array<YEvent<any>>,Transaction):void} f Observer function
     */
    unobserveDeep (f) {
      removeEventHandlerListener(this._dEH, f);
    }

    /**
     * @abstract
     * @return {any}
     */
    toJSON () {}
  }

  /**
   * @param {AbstractType<any>} type
   * @param {number} start
   * @param {number} end
   * @return {Array<any>}
   *
   * @private
   * @function
   */
  const typeListSlice = (type, start, end) => {
    if (start < 0) {
      start = type._length + start;
    }
    if (end < 0) {
      end = type._length + end;
    }
    let len = end - start;
    const cs = [];
    let n = type._start;
    while (n !== null && len > 0) {
      if (n.countable && !n.deleted) {
        const c = n.content.getContent();
        if (c.length <= start) {
          start -= c.length;
        } else {
          for (let i = start; i < c.length && len > 0; i++) {
            cs.push(c[i]);
            len--;
          }
          start = 0;
        }
      }
      n = n.right;
    }
    return cs
  };

  /**
   * @param {AbstractType<any>} type
   * @return {Array<any>}
   *
   * @private
   * @function
   */
  const typeListToArray = type => {
    const cs = [];
    let n = type._start;
    while (n !== null) {
      if (n.countable && !n.deleted) {
        const c = n.content.getContent();
        for (let i = 0; i < c.length; i++) {
          cs.push(c[i]);
        }
      }
      n = n.right;
    }
    return cs
  };

  /**
   * Executes a provided function on once on overy element of this YArray.
   *
   * @param {AbstractType<any>} type
   * @param {function(any,number,any):void} f A function to execute on every element of this YArray.
   *
   * @private
   * @function
   */
  const typeListForEach = (type, f) => {
    let index = 0;
    let n = type._start;
    while (n !== null) {
      if (n.countable && !n.deleted) {
        const c = n.content.getContent();
        for (let i = 0; i < c.length; i++) {
          f(c[i], index++, type);
        }
      }
      n = n.right;
    }
  };

  /**
   * @template C,R
   * @param {AbstractType<any>} type
   * @param {function(C,number,AbstractType<any>):R} f
   * @return {Array<R>}
   *
   * @private
   * @function
   */
  const typeListMap = (type, f) => {
    /**
     * @type {Array<any>}
     */
    const result = [];
    typeListForEach(type, (c, i) => {
      result.push(f(c, i, type));
    });
    return result
  };

  /**
   * @param {AbstractType<any>} type
   * @return {IterableIterator<any>}
   *
   * @private
   * @function
   */
  const typeListCreateIterator = type => {
    let n = type._start;
    /**
     * @type {Array<any>|null}
     */
    let currentContent = null;
    let currentContentIndex = 0;
    return {
      [Symbol.iterator] () {
        return this
      },
      next: () => {
        // find some content
        if (currentContent === null) {
          while (n !== null && n.deleted) {
            n = n.right;
          }
          // check if we reached the end, no need to check currentContent, because it does not exist
          if (n === null) {
            return {
              done: true,
              value: undefined
            }
          }
          // we found n, so we can set currentContent
          currentContent = n.content.getContent();
          currentContentIndex = 0;
          n = n.right; // we used the content of n, now iterate to next
        }
        const value = currentContent[currentContentIndex++];
        // check if we need to empty currentContent
        if (currentContent.length <= currentContentIndex) {
          currentContent = null;
        }
        return {
          done: false,
          value
        }
      }
    }
  };

  /**
   * @param {AbstractType<any>} type
   * @param {number} index
   * @return {any}
   *
   * @private
   * @function
   */
  const typeListGet = (type, index) => {
    const marker = findMarker(type, index);
    let n = type._start;
    if (marker !== null) {
      n = marker.p;
      index -= marker.index;
    }
    for (; n !== null; n = n.right) {
      if (!n.deleted && n.countable) {
        if (index < n.length) {
          return n.content.getContent()[index]
        }
        index -= n.length;
      }
    }
  };

  /**
   * @param {Transaction} transaction
   * @param {AbstractType<any>} parent
   * @param {Item?} referenceItem
   * @param {Array<Object<string,any>|Array<any>|boolean|number|null|string|Uint8Array>} content
   *
   * @private
   * @function
   */
  const typeListInsertGenericsAfter = (transaction, parent, referenceItem, content) => {
    let left = referenceItem;
    const doc = transaction.doc;
    const ownClientId = doc.clientID;
    const store = doc.store;
    const right = referenceItem === null ? parent._start : referenceItem.right;
    /**
     * @type {Array<Object|Array<any>|number|null>}
     */
    let jsonContent = [];
    const packJsonContent = () => {
      if (jsonContent.length > 0) {
        left = new Item(createID(ownClientId, getState(store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentAny(jsonContent));
        left.integrate(transaction, 0);
        jsonContent = [];
      }
    };
    content.forEach(c => {
      if (c === null) {
        jsonContent.push(c);
      } else {
        switch (c.constructor) {
          case Number:
          case Object:
          case Boolean:
          case Array:
          case String:
            jsonContent.push(c);
            break
          default:
            packJsonContent();
            switch (c.constructor) {
              case Uint8Array:
              case ArrayBuffer:
                left = new Item(createID(ownClientId, getState(store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentBinary(new Uint8Array(/** @type {Uint8Array} */ (c))));
                left.integrate(transaction, 0);
                break
              case Doc:
                left = new Item(createID(ownClientId, getState(store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentDoc(/** @type {Doc} */ (c)));
                left.integrate(transaction, 0);
                break
              default:
                if (c instanceof AbstractType) {
                  left = new Item(createID(ownClientId, getState(store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentType(c));
                  left.integrate(transaction, 0);
                } else {
                  throw new Error('Unexpected content type in insert operation')
                }
            }
        }
      }
    });
    packJsonContent();
  };

  const lengthExceeded = create$2('Length exceeded!');

  /**
   * @param {Transaction} transaction
   * @param {AbstractType<any>} parent
   * @param {number} index
   * @param {Array<Object<string,any>|Array<any>|number|null|string|Uint8Array>} content
   *
   * @private
   * @function
   */
  const typeListInsertGenerics = (transaction, parent, index, content) => {
    if (index > parent._length) {
      throw lengthExceeded
    }
    if (index === 0) {
      if (parent._searchMarker) {
        updateMarkerChanges(parent._searchMarker, index, content.length);
      }
      return typeListInsertGenericsAfter(transaction, parent, null, content)
    }
    const startIndex = index;
    const marker = findMarker(parent, index);
    let n = parent._start;
    if (marker !== null) {
      n = marker.p;
      index -= marker.index;
      // we need to iterate one to the left so that the algorithm works
      if (index === 0) {
        // @todo refactor this as it actually doesn't consider formats
        n = n.prev; // important! get the left undeleted item so that we can actually decrease index
        index += (n && n.countable && !n.deleted) ? n.length : 0;
      }
    }
    for (; n !== null; n = n.right) {
      if (!n.deleted && n.countable) {
        if (index <= n.length) {
          if (index < n.length) {
            // insert in-between
            getItemCleanStart(transaction, createID(n.id.client, n.id.clock + index));
          }
          break
        }
        index -= n.length;
      }
    }
    if (parent._searchMarker) {
      updateMarkerChanges(parent._searchMarker, startIndex, content.length);
    }
    return typeListInsertGenericsAfter(transaction, parent, n, content)
  };

  /**
   * Pushing content is special as we generally want to push after the last item. So we don't have to update
   * the serach marker.
   *
   * @param {Transaction} transaction
   * @param {AbstractType<any>} parent
   * @param {Array<Object<string,any>|Array<any>|number|null|string|Uint8Array>} content
   *
   * @private
   * @function
   */
  const typeListPushGenerics = (transaction, parent, content) => {
    // Use the marker with the highest index and iterate to the right.
    const marker = (parent._searchMarker || []).reduce((maxMarker, currMarker) => currMarker.index > maxMarker.index ? currMarker : maxMarker, { index: 0, p: parent._start });
    let n = marker.p;
    if (n) {
      while (n.right) {
        n = n.right;
      }
    }
    return typeListInsertGenericsAfter(transaction, parent, n, content)
  };

  /**
   * @param {Transaction} transaction
   * @param {AbstractType<any>} parent
   * @param {number} index
   * @param {number} length
   *
   * @private
   * @function
   */
  const typeListDelete = (transaction, parent, index, length) => {
    if (length === 0) { return }
    const startIndex = index;
    const startLength = length;
    const marker = findMarker(parent, index);
    let n = parent._start;
    if (marker !== null) {
      n = marker.p;
      index -= marker.index;
    }
    // compute the first item to be deleted
    for (; n !== null && index > 0; n = n.right) {
      if (!n.deleted && n.countable) {
        if (index < n.length) {
          getItemCleanStart(transaction, createID(n.id.client, n.id.clock + index));
        }
        index -= n.length;
      }
    }
    // delete all items until done
    while (length > 0 && n !== null) {
      if (!n.deleted) {
        if (length < n.length) {
          getItemCleanStart(transaction, createID(n.id.client, n.id.clock + length));
        }
        n.delete(transaction);
        length -= n.length;
      }
      n = n.right;
    }
    if (length > 0) {
      throw lengthExceeded
    }
    if (parent._searchMarker) {
      updateMarkerChanges(parent._searchMarker, startIndex, -startLength + length /* in case we remove the above exception */);
    }
  };

  /**
   * @param {Transaction} transaction
   * @param {AbstractType<any>} parent
   * @param {string} key
   *
   * @private
   * @function
   */
  const typeMapDelete = (transaction, parent, key) => {
    const c = parent._map.get(key);
    if (c !== undefined) {
      c.delete(transaction);
    }
  };

  /**
   * @param {Transaction} transaction
   * @param {AbstractType<any>} parent
   * @param {string} key
   * @param {Object|number|null|Array<any>|string|Uint8Array|AbstractType<any>} value
   *
   * @private
   * @function
   */
  const typeMapSet = (transaction, parent, key, value) => {
    const left = parent._map.get(key) || null;
    const doc = transaction.doc;
    const ownClientId = doc.clientID;
    let content;
    if (value == null) {
      content = new ContentAny([value]);
    } else {
      switch (value.constructor) {
        case Number:
        case Object:
        case Boolean:
        case Array:
        case String:
          content = new ContentAny([value]);
          break
        case Uint8Array:
          content = new ContentBinary(/** @type {Uint8Array} */ (value));
          break
        case Doc:
          content = new ContentDoc(/** @type {Doc} */ (value));
          break
        default:
          if (value instanceof AbstractType) {
            content = new ContentType(value);
          } else {
            throw new Error('Unexpected content type')
          }
      }
    }
    new Item(createID(ownClientId, getState(doc.store, ownClientId)), left, left && left.lastId, null, null, parent, key, content).integrate(transaction, 0);
  };

  /**
   * @param {AbstractType<any>} parent
   * @param {string} key
   * @return {Object<string,any>|number|null|Array<any>|string|Uint8Array|AbstractType<any>|undefined}
   *
   * @private
   * @function
   */
  const typeMapGet = (parent, key) => {
    const val = parent._map.get(key);
    return val !== undefined && !val.deleted ? val.content.getContent()[val.length - 1] : undefined
  };

  /**
   * @param {AbstractType<any>} parent
   * @return {Object<string,Object<string,any>|number|null|Array<any>|string|Uint8Array|AbstractType<any>|undefined>}
   *
   * @private
   * @function
   */
  const typeMapGetAll = (parent) => {
    /**
     * @type {Object<string,any>}
     */
    const res = {};
    parent._map.forEach((value, key) => {
      if (!value.deleted) {
        res[key] = value.content.getContent()[value.length - 1];
      }
    });
    return res
  };

  /**
   * @param {AbstractType<any>} parent
   * @param {string} key
   * @return {boolean}
   *
   * @private
   * @function
   */
  const typeMapHas = (parent, key) => {
    const val = parent._map.get(key);
    return val !== undefined && !val.deleted
  };

  /**
   * @param {Map<string,Item>} map
   * @return {IterableIterator<Array<any>>}
   *
   * @private
   * @function
   */
  const createMapIterator = map => iteratorFilter(map.entries(), /** @param {any} entry */ entry => !entry[1].deleted);

  /**
   * @module YArray
   */

  /**
   * Event that describes the changes on a YArray
   * @template T
   * @extends YEvent<YArray<T>>
   */
  class YArrayEvent extends YEvent {
    /**
     * @param {YArray<T>} yarray The changed type
     * @param {Transaction} transaction The transaction object
     */
    constructor (yarray, transaction) {
      super(yarray, transaction);
      this._transaction = transaction;
    }
  }

  /**
   * A shared Array implementation.
   * @template T
   * @extends AbstractType<YArrayEvent<T>>
   * @implements {Iterable<T>}
   */
  class YArray extends AbstractType {
    constructor () {
      super();
      /**
       * @type {Array<any>?}
       * @private
       */
      this._prelimContent = [];
      /**
       * @type {Array<ArraySearchMarker>}
       */
      this._searchMarker = [];
    }

    /**
     * Construct a new YArray containing the specified items.
     * @template {Object<string,any>|Array<any>|number|null|string|Uint8Array} T
     * @param {Array<T>} items
     * @return {YArray<T>}
     */
    static from (items) {
      /**
       * @type {YArray<T>}
       */
      const a = new YArray();
      a.push(items);
      return a
    }

    /**
     * Integrate this type into the Yjs instance.
     *
     * * Save this struct in the os
     * * This type is sent to other client
     * * Observer functions are fired
     *
     * @param {Doc} y The Yjs instance
     * @param {Item} item
     */
    _integrate (y, item) {
      super._integrate(y, item);
      this.insert(0, /** @type {Array<any>} */ (this._prelimContent));
      this._prelimContent = null;
    }

    /**
     * @return {YArray<T>}
     */
    _copy () {
      return new YArray()
    }

    /**
     * @return {YArray<T>}
     */
    clone () {
      /**
       * @type {YArray<T>}
       */
      const arr = new YArray();
      arr.insert(0, this.toArray().map(el =>
        el instanceof AbstractType ? /** @type {typeof el} */ (el.clone()) : el
      ));
      return arr
    }

    get length () {
      return this._prelimContent === null ? this._length : this._prelimContent.length
    }

    /**
     * Creates YArrayEvent and calls observers.
     *
     * @param {Transaction} transaction
     * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
     */
    _callObserver (transaction, parentSubs) {
      super._callObserver(transaction, parentSubs);
      callTypeObservers(this, transaction, new YArrayEvent(this, transaction));
    }

    /**
     * Inserts new content at an index.
     *
     * Important: This function expects an array of content. Not just a content
     * object. The reason for this "weirdness" is that inserting several elements
     * is very efficient when it is done as a single operation.
     *
     * @example
     *  // Insert character 'a' at position 0
     *  yarray.insert(0, ['a'])
     *  // Insert numbers 1, 2 at position 1
     *  yarray.insert(1, [1, 2])
     *
     * @param {number} index The index to insert content at.
     * @param {Array<T>} content The array of content
     */
    insert (index, content) {
      if (this.doc !== null) {
        transact(this.doc, transaction => {
          typeListInsertGenerics(transaction, this, index, /** @type {any} */ (content));
        });
      } else {
        /** @type {Array<any>} */ (this._prelimContent).splice(index, 0, ...content);
      }
    }

    /**
     * Appends content to this YArray.
     *
     * @param {Array<T>} content Array of content to append.
     *
     * @todo Use the following implementation in all types.
     */
    push (content) {
      if (this.doc !== null) {
        transact(this.doc, transaction => {
          typeListPushGenerics(transaction, this, /** @type {any} */ (content));
        });
      } else {
        /** @type {Array<any>} */ (this._prelimContent).push(...content);
      }
    }

    /**
     * Preppends content to this YArray.
     *
     * @param {Array<T>} content Array of content to preppend.
     */
    unshift (content) {
      this.insert(0, content);
    }

    /**
     * Deletes elements starting from an index.
     *
     * @param {number} index Index at which to start deleting elements
     * @param {number} length The number of elements to remove. Defaults to 1.
     */
    delete (index, length = 1) {
      if (this.doc !== null) {
        transact(this.doc, transaction => {
          typeListDelete(transaction, this, index, length);
        });
      } else {
        /** @type {Array<any>} */ (this._prelimContent).splice(index, length);
      }
    }

    /**
     * Returns the i-th element from a YArray.
     *
     * @param {number} index The index of the element to return from the YArray
     * @return {T}
     */
    get (index) {
      return typeListGet(this, index)
    }

    /**
     * Transforms this YArray to a JavaScript Array.
     *
     * @return {Array<T>}
     */
    toArray () {
      return typeListToArray(this)
    }

    /**
     * Transforms this YArray to a JavaScript Array.
     *
     * @param {number} [start]
     * @param {number} [end]
     * @return {Array<T>}
     */
    slice (start = 0, end = this.length) {
      return typeListSlice(this, start, end)
    }

    /**
     * Transforms this Shared Type to a JSON object.
     *
     * @return {Array<any>}
     */
    toJSON () {
      return this.map(c => c instanceof AbstractType ? c.toJSON() : c)
    }

    /**
     * Returns an Array with the result of calling a provided function on every
     * element of this YArray.
     *
     * @template M
     * @param {function(T,number,YArray<T>):M} f Function that produces an element of the new Array
     * @return {Array<M>} A new array with each element being the result of the
     *                 callback function
     */
    map (f) {
      return typeListMap(this, /** @type {any} */ (f))
    }

    /**
     * Executes a provided function once on overy element of this YArray.
     *
     * @param {function(T,number,YArray<T>):void} f A function to execute on every element of this YArray.
     */
    forEach (f) {
      typeListForEach(this, f);
    }

    /**
     * @return {IterableIterator<T>}
     */
    [Symbol.iterator] () {
      return typeListCreateIterator(this)
    }

    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
     */
    _write (encoder) {
      encoder.writeTypeRef(YArrayRefID);
    }
  }

  /**
   * @template T
   * @extends YEvent<YMap<T>>
   * Event that describes the changes on a YMap.
   */
  class YMapEvent extends YEvent {
    /**
     * @param {YMap<T>} ymap The YArray that changed.
     * @param {Transaction} transaction
     * @param {Set<any>} subs The keys that changed.
     */
    constructor (ymap, transaction, subs) {
      super(ymap, transaction);
      this.keysChanged = subs;
    }
  }

  /**
   * @template MapType
   * A shared Map implementation.
   *
   * @extends AbstractType<YMapEvent<MapType>>
   * @implements {Iterable<MapType>}
   */
  class YMap extends AbstractType {
    /**
     *
     * @param {Iterable<readonly [string, any]>=} entries - an optional iterable to initialize the YMap
     */
    constructor (entries) {
      super();
      /**
       * @type {Map<string,any>?}
       * @private
       */
      this._prelimContent = null;

      if (entries === undefined) {
        this._prelimContent = new Map();
      } else {
        this._prelimContent = new Map(entries);
      }
    }

    /**
     * Integrate this type into the Yjs instance.
     *
     * * Save this struct in the os
     * * This type is sent to other client
     * * Observer functions are fired
     *
     * @param {Doc} y The Yjs instance
     * @param {Item} item
     */
    _integrate (y, item) {
      super._integrate(y, item)
      ;/** @type {Map<string, any>} */ (this._prelimContent).forEach((value, key) => {
        this.set(key, value);
      });
      this._prelimContent = null;
    }

    /**
     * @return {YMap<MapType>}
     */
    _copy () {
      return new YMap()
    }

    /**
     * @return {YMap<MapType>}
     */
    clone () {
      /**
       * @type {YMap<MapType>}
       */
      const map = new YMap();
      this.forEach((value, key) => {
        map.set(key, value instanceof AbstractType ? /** @type {typeof value} */ (value.clone()) : value);
      });
      return map
    }

    /**
     * Creates YMapEvent and calls observers.
     *
     * @param {Transaction} transaction
     * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
     */
    _callObserver (transaction, parentSubs) {
      callTypeObservers(this, transaction, new YMapEvent(this, transaction, parentSubs));
    }

    /**
     * Transforms this Shared Type to a JSON object.
     *
     * @return {Object<string,any>}
     */
    toJSON () {
      /**
       * @type {Object<string,MapType>}
       */
      const map = {};
      this._map.forEach((item, key) => {
        if (!item.deleted) {
          const v = item.content.getContent()[item.length - 1];
          map[key] = v instanceof AbstractType ? v.toJSON() : v;
        }
      });
      return map
    }

    /**
     * Returns the size of the YMap (count of key/value pairs)
     *
     * @return {number}
     */
    get size () {
      return [...createMapIterator(this._map)].length
    }

    /**
     * Returns the keys for each element in the YMap Type.
     *
     * @return {IterableIterator<string>}
     */
    keys () {
      return iteratorMap(createMapIterator(this._map), /** @param {any} v */ v => v[0])
    }

    /**
     * Returns the values for each element in the YMap Type.
     *
     * @return {IterableIterator<any>}
     */
    values () {
      return iteratorMap(createMapIterator(this._map), /** @param {any} v */ v => v[1].content.getContent()[v[1].length - 1])
    }

    /**
     * Returns an Iterator of [key, value] pairs
     *
     * @return {IterableIterator<any>}
     */
    entries () {
      return iteratorMap(createMapIterator(this._map), /** @param {any} v */ v => [v[0], v[1].content.getContent()[v[1].length - 1]])
    }

    /**
     * Executes a provided function on once on every key-value pair.
     *
     * @param {function(MapType,string,YMap<MapType>):void} f A function to execute on every element of this YArray.
     */
    forEach (f) {
      this._map.forEach((item, key) => {
        if (!item.deleted) {
          f(item.content.getContent()[item.length - 1], key, this);
        }
      });
    }

    /**
     * Returns an Iterator of [key, value] pairs
     *
     * @return {IterableIterator<any>}
     */
    [Symbol.iterator] () {
      return this.entries()
    }

    /**
     * Remove a specified element from this YMap.
     *
     * @param {string} key The key of the element to remove.
     */
    delete (key) {
      if (this.doc !== null) {
        transact(this.doc, transaction => {
          typeMapDelete(transaction, this, key);
        });
      } else {
        /** @type {Map<string, any>} */ (this._prelimContent).delete(key);
      }
    }

    /**
     * Adds or updates an element with a specified key and value.
     * @template {MapType} VAL
     *
     * @param {string} key The key of the element to add to this YMap
     * @param {VAL} value The value of the element to add
     * @return {VAL}
     */
    set (key, value) {
      if (this.doc !== null) {
        transact(this.doc, transaction => {
          typeMapSet(transaction, this, key, /** @type {any} */ (value));
        });
      } else {
        /** @type {Map<string, any>} */ (this._prelimContent).set(key, value);
      }
      return value
    }

    /**
     * Returns a specified element from this YMap.
     *
     * @param {string} key
     * @return {MapType|undefined}
     */
    get (key) {
      return /** @type {any} */ (typeMapGet(this, key))
    }

    /**
     * Returns a boolean indicating whether the specified key exists or not.
     *
     * @param {string} key The key to test.
     * @return {boolean}
     */
    has (key) {
      return typeMapHas(this, key)
    }

    /**
     * Removes all elements from this YMap.
     */
    clear () {
      if (this.doc !== null) {
        transact(this.doc, transaction => {
          this.forEach(function (_value, key, map) {
            typeMapDelete(transaction, map, key);
          });
        });
      } else {
        /** @type {Map<string, any>} */ (this._prelimContent).clear();
      }
    }

    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
     */
    _write (encoder) {
      encoder.writeTypeRef(YMapRefID);
    }
  }

  /**
   * @param {any} a
   * @param {any} b
   * @return {boolean}
   */
  const equalAttrs = (a, b) => a === b || (typeof a === 'object' && typeof b === 'object' && a && b && equalFlat(a, b));

  class ItemTextListPosition {
    /**
     * @param {Item|null} left
     * @param {Item|null} right
     * @param {number} index
     * @param {Map<string,any>} currentAttributes
     */
    constructor (left, right, index, currentAttributes) {
      this.left = left;
      this.right = right;
      this.index = index;
      this.currentAttributes = currentAttributes;
    }

    /**
     * Only call this if you know that this.right is defined
     */
    forward () {
      if (this.right === null) {
        unexpectedCase();
      }
      switch (this.right.content.constructor) {
        case ContentFormat:
          if (!this.right.deleted) {
            updateCurrentAttributes(this.currentAttributes, /** @type {ContentFormat} */ (this.right.content));
          }
          break
        default:
          if (!this.right.deleted) {
            this.index += this.right.length;
          }
          break
      }
      this.left = this.right;
      this.right = this.right.right;
    }
  }

  /**
   * @param {Transaction} transaction
   * @param {ItemTextListPosition} pos
   * @param {number} count steps to move forward
   * @return {ItemTextListPosition}
   *
   * @private
   * @function
   */
  const findNextPosition = (transaction, pos, count) => {
    while (pos.right !== null && count > 0) {
      switch (pos.right.content.constructor) {
        case ContentFormat:
          if (!pos.right.deleted) {
            updateCurrentAttributes(pos.currentAttributes, /** @type {ContentFormat} */ (pos.right.content));
          }
          break
        default:
          if (!pos.right.deleted) {
            if (count < pos.right.length) {
              // split right
              getItemCleanStart(transaction, createID(pos.right.id.client, pos.right.id.clock + count));
            }
            pos.index += pos.right.length;
            count -= pos.right.length;
          }
          break
      }
      pos.left = pos.right;
      pos.right = pos.right.right;
      // pos.forward() - we don't forward because that would halve the performance because we already do the checks above
    }
    return pos
  };

  /**
   * @param {Transaction} transaction
   * @param {AbstractType<any>} parent
   * @param {number} index
   * @return {ItemTextListPosition}
   *
   * @private
   * @function
   */
  const findPosition = (transaction, parent, index) => {
    const currentAttributes = new Map();
    const marker = findMarker(parent, index);
    if (marker) {
      const pos = new ItemTextListPosition(marker.p.left, marker.p, marker.index, currentAttributes);
      return findNextPosition(transaction, pos, index - marker.index)
    } else {
      const pos = new ItemTextListPosition(null, parent._start, 0, currentAttributes);
      return findNextPosition(transaction, pos, index)
    }
  };

  /**
   * Negate applied formats
   *
   * @param {Transaction} transaction
   * @param {AbstractType<any>} parent
   * @param {ItemTextListPosition} currPos
   * @param {Map<string,any>} negatedAttributes
   *
   * @private
   * @function
   */
  const insertNegatedAttributes = (transaction, parent, currPos, negatedAttributes) => {
    // check if we really need to remove attributes
    while (
      currPos.right !== null && (
        currPos.right.deleted === true || (
          currPos.right.content.constructor === ContentFormat &&
          equalAttrs(negatedAttributes.get(/** @type {ContentFormat} */ (currPos.right.content).key), /** @type {ContentFormat} */ (currPos.right.content).value)
        )
      )
    ) {
      if (!currPos.right.deleted) {
        negatedAttributes.delete(/** @type {ContentFormat} */ (currPos.right.content).key);
      }
      currPos.forward();
    }
    const doc = transaction.doc;
    const ownClientId = doc.clientID;
    negatedAttributes.forEach((val, key) => {
      const left = currPos.left;
      const right = currPos.right;
      const nextFormat = new Item(createID(ownClientId, getState(doc.store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentFormat(key, val));
      nextFormat.integrate(transaction, 0);
      currPos.right = nextFormat;
      currPos.forward();
    });
  };

  /**
   * @param {Map<string,any>} currentAttributes
   * @param {ContentFormat} format
   *
   * @private
   * @function
   */
  const updateCurrentAttributes = (currentAttributes, format) => {
    const { key, value } = format;
    if (value === null) {
      currentAttributes.delete(key);
    } else {
      currentAttributes.set(key, value);
    }
  };

  /**
   * @param {ItemTextListPosition} currPos
   * @param {Object<string,any>} attributes
   *
   * @private
   * @function
   */
  const minimizeAttributeChanges = (currPos, attributes) => {
    // go right while attributes[right.key] === right.value (or right is deleted)
    while (true) {
      if (currPos.right === null) {
        break
      } else if (currPos.right.deleted || (currPos.right.content.constructor === ContentFormat && equalAttrs(attributes[(/** @type {ContentFormat} */ (currPos.right.content)).key] || null, /** @type {ContentFormat} */ (currPos.right.content).value))) ; else {
        break
      }
      currPos.forward();
    }
  };

  /**
   * @param {Transaction} transaction
   * @param {AbstractType<any>} parent
   * @param {ItemTextListPosition} currPos
   * @param {Object<string,any>} attributes
   * @return {Map<string,any>}
   *
   * @private
   * @function
   **/
  const insertAttributes = (transaction, parent, currPos, attributes) => {
    const doc = transaction.doc;
    const ownClientId = doc.clientID;
    const negatedAttributes = new Map();
    // insert format-start items
    for (const key in attributes) {
      const val = attributes[key];
      const currentVal = currPos.currentAttributes.get(key) || null;
      if (!equalAttrs(currentVal, val)) {
        // save negated attribute (set null if currentVal undefined)
        negatedAttributes.set(key, currentVal);
        const { left, right } = currPos;
        currPos.right = new Item(createID(ownClientId, getState(doc.store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentFormat(key, val));
        currPos.right.integrate(transaction, 0);
        currPos.forward();
      }
    }
    return negatedAttributes
  };

  /**
   * @param {Transaction} transaction
   * @param {AbstractType<any>} parent
   * @param {ItemTextListPosition} currPos
   * @param {string|object|AbstractType<any>} text
   * @param {Object<string,any>} attributes
   *
   * @private
   * @function
   **/
  const insertText = (transaction, parent, currPos, text, attributes) => {
    currPos.currentAttributes.forEach((_val, key) => {
      if (attributes[key] === undefined) {
        attributes[key] = null;
      }
    });
    const doc = transaction.doc;
    const ownClientId = doc.clientID;
    minimizeAttributeChanges(currPos, attributes);
    const negatedAttributes = insertAttributes(transaction, parent, currPos, attributes);
    // insert content
    const content = text.constructor === String ? new ContentString(/** @type {string} */ (text)) : (text instanceof AbstractType ? new ContentType(text) : new ContentEmbed(text));
    let { left, right, index } = currPos;
    if (parent._searchMarker) {
      updateMarkerChanges(parent._searchMarker, currPos.index, content.getLength());
    }
    right = new Item(createID(ownClientId, getState(doc.store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, content);
    right.integrate(transaction, 0);
    currPos.right = right;
    currPos.index = index;
    currPos.forward();
    insertNegatedAttributes(transaction, parent, currPos, negatedAttributes);
  };

  /**
   * @param {Transaction} transaction
   * @param {AbstractType<any>} parent
   * @param {ItemTextListPosition} currPos
   * @param {number} length
   * @param {Object<string,any>} attributes
   *
   * @private
   * @function
   */
  const formatText = (transaction, parent, currPos, length, attributes) => {
    const doc = transaction.doc;
    const ownClientId = doc.clientID;
    minimizeAttributeChanges(currPos, attributes);
    const negatedAttributes = insertAttributes(transaction, parent, currPos, attributes);
    // iterate until first non-format or null is found
    // delete all formats with attributes[format.key] != null
    // also check the attributes after the first non-format as we do not want to insert redundant negated attributes there
    // eslint-disable-next-line no-labels
    iterationLoop: while (
      currPos.right !== null &&
      (length > 0 ||
        (
          negatedAttributes.size > 0 &&
          (currPos.right.deleted || currPos.right.content.constructor === ContentFormat)
        )
      )
    ) {
      if (!currPos.right.deleted) {
        switch (currPos.right.content.constructor) {
          case ContentFormat: {
            const { key, value } = /** @type {ContentFormat} */ (currPos.right.content);
            const attr = attributes[key];
            if (attr !== undefined) {
              if (equalAttrs(attr, value)) {
                negatedAttributes.delete(key);
              } else {
                if (length === 0) {
                  // no need to further extend negatedAttributes
                  // eslint-disable-next-line no-labels
                  break iterationLoop
                }
                negatedAttributes.set(key, value);
              }
              currPos.right.delete(transaction);
            } else {
              currPos.currentAttributes.set(key, value);
            }
            break
          }
          default:
            if (length < currPos.right.length) {
              getItemCleanStart(transaction, createID(currPos.right.id.client, currPos.right.id.clock + length));
            }
            length -= currPos.right.length;
            break
        }
      }
      currPos.forward();
    }
    // Quill just assumes that the editor starts with a newline and that it always
    // ends with a newline. We only insert that newline when a new newline is
    // inserted - i.e when length is bigger than type.length
    if (length > 0) {
      let newlines = '';
      for (; length > 0; length--) {
        newlines += '\n';
      }
      currPos.right = new Item(createID(ownClientId, getState(doc.store, ownClientId)), currPos.left, currPos.left && currPos.left.lastId, currPos.right, currPos.right && currPos.right.id, parent, null, new ContentString(newlines));
      currPos.right.integrate(transaction, 0);
      currPos.forward();
    }
    insertNegatedAttributes(transaction, parent, currPos, negatedAttributes);
  };

  /**
   * Call this function after string content has been deleted in order to
   * clean up formatting Items.
   *
   * @param {Transaction} transaction
   * @param {Item} start
   * @param {Item|null} curr exclusive end, automatically iterates to the next Content Item
   * @param {Map<string,any>} startAttributes
   * @param {Map<string,any>} currAttributes
   * @return {number} The amount of formatting Items deleted.
   *
   * @function
   */
  const cleanupFormattingGap = (transaction, start, curr, startAttributes, currAttributes) => {
    /**
     * @type {Item|null}
     */
    let end = start;
    /**
     * @type {Map<string,ContentFormat>}
     */
    const endFormats = create$6();
    while (end && (!end.countable || end.deleted)) {
      if (!end.deleted && end.content.constructor === ContentFormat) {
        const cf = /** @type {ContentFormat} */ (end.content);
        endFormats.set(cf.key, cf);
      }
      end = end.right;
    }
    let cleanups = 0;
    let reachedCurr = false;
    while (start !== end) {
      if (curr === start) {
        reachedCurr = true;
      }
      if (!start.deleted) {
        const content = start.content;
        switch (content.constructor) {
          case ContentFormat: {
            const { key, value } = /** @type {ContentFormat} */ (content);
            const startAttrValue = startAttributes.get(key) || null;
            if (endFormats.get(key) !== content || startAttrValue === value) {
              // Either this format is overwritten or it is not necessary because the attribute already existed.
              start.delete(transaction);
              cleanups++;
              if (!reachedCurr && (currAttributes.get(key) || null) === value && startAttrValue !== value) {
                if (startAttrValue === null) {
                  currAttributes.delete(key);
                } else {
                  currAttributes.set(key, startAttrValue);
                }
              }
            }
            if (!reachedCurr && !start.deleted) {
              updateCurrentAttributes(currAttributes, /** @type {ContentFormat} */ (content));
            }
            break
          }
        }
      }
      start = /** @type {Item} */ (start.right);
    }
    return cleanups
  };

  /**
   * @param {Transaction} transaction
   * @param {Item | null} item
   */
  const cleanupContextlessFormattingGap = (transaction, item) => {
    // iterate until item.right is null or content
    while (item && item.right && (item.right.deleted || !item.right.countable)) {
      item = item.right;
    }
    const attrs = new Set();
    // iterate back until a content item is found
    while (item && (item.deleted || !item.countable)) {
      if (!item.deleted && item.content.constructor === ContentFormat) {
        const key = /** @type {ContentFormat} */ (item.content).key;
        if (attrs.has(key)) {
          item.delete(transaction);
        } else {
          attrs.add(key);
        }
      }
      item = item.left;
    }
  };

  /**
   * This function is experimental and subject to change / be removed.
   *
   * Ideally, we don't need this function at all. Formatting attributes should be cleaned up
   * automatically after each change. This function iterates twice over the complete YText type
   * and removes unnecessary formatting attributes. This is also helpful for testing.
   *
   * This function won't be exported anymore as soon as there is confidence that the YText type works as intended.
   *
   * @param {YText} type
   * @return {number} How many formatting attributes have been cleaned up.
   */
  const cleanupYTextFormatting = type => {
    let res = 0;
    transact(/** @type {Doc} */ (type.doc), transaction => {
      let start = /** @type {Item} */ (type._start);
      let end = type._start;
      let startAttributes = create$6();
      const currentAttributes = copy(startAttributes);
      while (end) {
        if (end.deleted === false) {
          switch (end.content.constructor) {
            case ContentFormat:
              updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (end.content));
              break
            default:
              res += cleanupFormattingGap(transaction, start, end, startAttributes, currentAttributes);
              startAttributes = copy(currentAttributes);
              start = end;
              break
          }
        }
        end = end.right;
      }
    });
    return res
  };

  /**
   * This will be called by the transction once the event handlers are called to potentially cleanup
   * formatting attributes.
   *
   * @param {Transaction} transaction
   */
  const cleanupYTextAfterTransaction = transaction => {
    /**
     * @type {Set<YText>}
     */
    const needFullCleanup = new Set();
    // check if another formatting item was inserted
    const doc = transaction.doc;
    for (const [client, afterClock] of transaction.afterState.entries()) {
      const clock = transaction.beforeState.get(client) || 0;
      if (afterClock === clock) {
        continue
      }
      iterateStructs(transaction, /** @type {Array<Item|GC>} */ (doc.store.clients.get(client)), clock, afterClock, item => {
        if (
          !item.deleted && /** @type {Item} */ (item).content.constructor === ContentFormat && item.constructor !== GC
        ) {
          needFullCleanup.add(/** @type {any} */ (item).parent);
        }
      });
    }
    // cleanup in a new transaction
    transact(doc, (t) => {
      iterateDeletedStructs(transaction, transaction.deleteSet, item => {
        if (item instanceof GC || !(/** @type {YText} */ (item.parent)._hasFormatting) || needFullCleanup.has(/** @type {YText} */ (item.parent))) {
          return
        }
        const parent = /** @type {YText} */ (item.parent);
        if (item.content.constructor === ContentFormat) {
          needFullCleanup.add(parent);
        } else {
          // If no formatting attribute was inserted or deleted, we can make due with contextless
          // formatting cleanups.
          // Contextless: it is not necessary to compute currentAttributes for the affected position.
          cleanupContextlessFormattingGap(t, item);
        }
      });
      // If a formatting item was inserted, we simply clean the whole type.
      // We need to compute currentAttributes for the current position anyway.
      for (const yText of needFullCleanup) {
        cleanupYTextFormatting(yText);
      }
    });
  };

  /**
   * @param {Transaction} transaction
   * @param {ItemTextListPosition} currPos
   * @param {number} length
   * @return {ItemTextListPosition}
   *
   * @private
   * @function
   */
  const deleteText = (transaction, currPos, length) => {
    const startLength = length;
    const startAttrs = copy(currPos.currentAttributes);
    const start = currPos.right;
    while (length > 0 && currPos.right !== null) {
      if (currPos.right.deleted === false) {
        switch (currPos.right.content.constructor) {
          case ContentType:
          case ContentEmbed:
          case ContentString:
            if (length < currPos.right.length) {
              getItemCleanStart(transaction, createID(currPos.right.id.client, currPos.right.id.clock + length));
            }
            length -= currPos.right.length;
            currPos.right.delete(transaction);
            break
        }
      }
      currPos.forward();
    }
    if (start) {
      cleanupFormattingGap(transaction, start, currPos.right, startAttrs, currPos.currentAttributes);
    }
    const parent = /** @type {AbstractType<any>} */ (/** @type {Item} */ (currPos.left || currPos.right).parent);
    if (parent._searchMarker) {
      updateMarkerChanges(parent._searchMarker, currPos.index, -startLength + length);
    }
    return currPos
  };

  /**
   * The Quill Delta format represents changes on a text document with
   * formatting information. For mor information visit {@link https://quilljs.com/docs/delta/|Quill Delta}
   *
   * @example
   *   {
   *     ops: [
   *       { insert: 'Gandalf', attributes: { bold: true } },
   *       { insert: ' the ' },
   *       { insert: 'Grey', attributes: { color: '#cccccc' } }
   *     ]
   *   }
   *
   */

  /**
    * Attributes that can be assigned to a selection of text.
    *
    * @example
    *   {
    *     bold: true,
    *     font-size: '40px'
    *   }
    *
    * @typedef {Object} TextAttributes
    */

  /**
   * @extends YEvent<YText>
   * Event that describes the changes on a YText type.
   */
  class YTextEvent extends YEvent {
    /**
     * @param {YText} ytext
     * @param {Transaction} transaction
     * @param {Set<any>} subs The keys that changed
     */
    constructor (ytext, transaction, subs) {
      super(ytext, transaction);
      /**
       * Whether the children changed.
       * @type {Boolean}
       * @private
       */
      this.childListChanged = false;
      /**
       * Set of all changed attributes.
       * @type {Set<string>}
       */
      this.keysChanged = new Set();
      subs.forEach((sub) => {
        if (sub === null) {
          this.childListChanged = true;
        } else {
          this.keysChanged.add(sub);
        }
      });
    }

    /**
     * @type {{added:Set<Item>,deleted:Set<Item>,keys:Map<string,{action:'add'|'update'|'delete',oldValue:any}>,delta:Array<{insert?:Array<any>|string, delete?:number, retain?:number}>}}
     */
    get changes () {
      if (this._changes === null) {
        /**
         * @type {{added:Set<Item>,deleted:Set<Item>,keys:Map<string,{action:'add'|'update'|'delete',oldValue:any}>,delta:Array<{insert?:Array<any>|string|AbstractType<any>|object, delete?:number, retain?:number}>}}
         */
        const changes = {
          keys: this.keys,
          delta: this.delta,
          added: new Set(),
          deleted: new Set()
        };
        this._changes = changes;
      }
      return /** @type {any} */ (this._changes)
    }

    /**
     * Compute the changes in the delta format.
     * A {@link https://quilljs.com/docs/delta/|Quill Delta}) that represents the changes on the document.
     *
     * @type {Array<{insert?:string|object|AbstractType<any>, delete?:number, retain?:number, attributes?: Object<string,any>}>}
     *
     * @public
     */
    get delta () {
      if (this._delta === null) {
        const y = /** @type {Doc} */ (this.target.doc);
        /**
         * @type {Array<{insert?:string|object|AbstractType<any>, delete?:number, retain?:number, attributes?: Object<string,any>}>}
         */
        const delta = [];
        transact(y, transaction => {
          const currentAttributes = new Map(); // saves all current attributes for insert
          const oldAttributes = new Map();
          let item = this.target._start;
          /**
           * @type {string?}
           */
          let action = null;
          /**
           * @type {Object<string,any>}
           */
          const attributes = {}; // counts added or removed new attributes for retain
          /**
           * @type {string|object}
           */
          let insert = '';
          let retain = 0;
          let deleteLen = 0;
          const addOp = () => {
            if (action !== null) {
              /**
               * @type {any}
               */
              let op = null;
              switch (action) {
                case 'delete':
                  if (deleteLen > 0) {
                    op = { delete: deleteLen };
                  }
                  deleteLen = 0;
                  break
                case 'insert':
                  if (typeof insert === 'object' || insert.length > 0) {
                    op = { insert };
                    if (currentAttributes.size > 0) {
                      op.attributes = {};
                      currentAttributes.forEach((value, key) => {
                        if (value !== null) {
                          op.attributes[key] = value;
                        }
                      });
                    }
                  }
                  insert = '';
                  break
                case 'retain':
                  if (retain > 0) {
                    op = { retain };
                    if (!isEmpty(attributes)) {
                      op.attributes = assign({}, attributes);
                    }
                  }
                  retain = 0;
                  break
              }
              if (op) delta.push(op);
              action = null;
            }
          };
          while (item !== null) {
            switch (item.content.constructor) {
              case ContentType:
              case ContentEmbed:
                if (this.adds(item)) {
                  if (!this.deletes(item)) {
                    addOp();
                    action = 'insert';
                    insert = item.content.getContent()[0];
                    addOp();
                  }
                } else if (this.deletes(item)) {
                  if (action !== 'delete') {
                    addOp();
                    action = 'delete';
                  }
                  deleteLen += 1;
                } else if (!item.deleted) {
                  if (action !== 'retain') {
                    addOp();
                    action = 'retain';
                  }
                  retain += 1;
                }
                break
              case ContentString:
                if (this.adds(item)) {
                  if (!this.deletes(item)) {
                    if (action !== 'insert') {
                      addOp();
                      action = 'insert';
                    }
                    insert += /** @type {ContentString} */ (item.content).str;
                  }
                } else if (this.deletes(item)) {
                  if (action !== 'delete') {
                    addOp();
                    action = 'delete';
                  }
                  deleteLen += item.length;
                } else if (!item.deleted) {
                  if (action !== 'retain') {
                    addOp();
                    action = 'retain';
                  }
                  retain += item.length;
                }
                break
              case ContentFormat: {
                const { key, value } = /** @type {ContentFormat} */ (item.content);
                if (this.adds(item)) {
                  if (!this.deletes(item)) {
                    const curVal = currentAttributes.get(key) || null;
                    if (!equalAttrs(curVal, value)) {
                      if (action === 'retain') {
                        addOp();
                      }
                      if (equalAttrs(value, (oldAttributes.get(key) || null))) {
                        delete attributes[key];
                      } else {
                        attributes[key] = value;
                      }
                    } else if (value !== null) {
                      item.delete(transaction);
                    }
                  }
                } else if (this.deletes(item)) {
                  oldAttributes.set(key, value);
                  const curVal = currentAttributes.get(key) || null;
                  if (!equalAttrs(curVal, value)) {
                    if (action === 'retain') {
                      addOp();
                    }
                    attributes[key] = curVal;
                  }
                } else if (!item.deleted) {
                  oldAttributes.set(key, value);
                  const attr = attributes[key];
                  if (attr !== undefined) {
                    if (!equalAttrs(attr, value)) {
                      if (action === 'retain') {
                        addOp();
                      }
                      if (value === null) {
                        delete attributes[key];
                      } else {
                        attributes[key] = value;
                      }
                    } else if (attr !== null) { // this will be cleaned up automatically by the contextless cleanup function
                      item.delete(transaction);
                    }
                  }
                }
                if (!item.deleted) {
                  if (action === 'insert') {
                    addOp();
                  }
                  updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (item.content));
                }
                break
              }
            }
            item = item.right;
          }
          addOp();
          while (delta.length > 0) {
            const lastOp = delta[delta.length - 1];
            if (lastOp.retain !== undefined && lastOp.attributes === undefined) {
              // retain delta's if they don't assign attributes
              delta.pop();
            } else {
              break
            }
          }
        });
        this._delta = delta;
      }
      return /** @type {any} */ (this._delta)
    }
  }

  /**
   * Type that represents text with formatting information.
   *
   * This type replaces y-richtext as this implementation is able to handle
   * block formats (format information on a paragraph), embeds (complex elements
   * like pictures and videos), and text formats (**bold**, *italic*).
   *
   * @extends AbstractType<YTextEvent>
   */
  class YText extends AbstractType {
    /**
     * @param {String} [string] The initial value of the YText.
     */
    constructor (string) {
      super();
      /**
       * Array of pending operations on this type
       * @type {Array<function():void>?}
       */
      this._pending = string !== undefined ? [() => this.insert(0, string)] : [];
      /**
       * @type {Array<ArraySearchMarker>|null}
       */
      this._searchMarker = [];
      /**
       * Whether this YText contains formatting attributes.
       * This flag is updated when a formatting item is integrated (see ContentFormat.integrate)
       */
      this._hasFormatting = false;
    }

    /**
     * Number of characters of this text type.
     *
     * @type {number}
     */
    get length () {
      return this._length
    }

    /**
     * @param {Doc} y
     * @param {Item} item
     */
    _integrate (y, item) {
      super._integrate(y, item);
      try {
        /** @type {Array<function>} */ (this._pending).forEach(f => f());
      } catch (e) {
        console.error(e);
      }
      this._pending = null;
    }

    _copy () {
      return new YText()
    }

    /**
     * @return {YText}
     */
    clone () {
      const text = new YText();
      text.applyDelta(this.toDelta());
      return text
    }

    /**
     * Creates YTextEvent and calls observers.
     *
     * @param {Transaction} transaction
     * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
     */
    _callObserver (transaction, parentSubs) {
      super._callObserver(transaction, parentSubs);
      const event = new YTextEvent(this, transaction, parentSubs);
      callTypeObservers(this, transaction, event);
      // If a remote change happened, we try to cleanup potential formatting duplicates.
      if (!transaction.local && this._hasFormatting) {
        transaction._needFormattingCleanup = true;
      }
    }

    /**
     * Returns the unformatted string representation of this YText type.
     *
     * @public
     */
    toString () {
      let str = '';
      /**
       * @type {Item|null}
       */
      let n = this._start;
      while (n !== null) {
        if (!n.deleted && n.countable && n.content.constructor === ContentString) {
          str += /** @type {ContentString} */ (n.content).str;
        }
        n = n.right;
      }
      return str
    }

    /**
     * Returns the unformatted string representation of this YText type.
     *
     * @return {string}
     * @public
     */
    toJSON () {
      return this.toString()
    }

    /**
     * Apply a {@link Delta} on this shared YText type.
     *
     * @param {any} delta The changes to apply on this element.
     * @param {object}  opts
     * @param {boolean} [opts.sanitize] Sanitize input delta. Removes ending newlines if set to true.
     *
     *
     * @public
     */
    applyDelta (delta, { sanitize = true } = {}) {
      if (this.doc !== null) {
        transact(this.doc, transaction => {
          const currPos = new ItemTextListPosition(null, this._start, 0, new Map());
          for (let i = 0; i < delta.length; i++) {
            const op = delta[i];
            if (op.insert !== undefined) {
              // Quill assumes that the content starts with an empty paragraph.
              // Yjs/Y.Text assumes that it starts empty. We always hide that
              // there is a newline at the end of the content.
              // If we omit this step, clients will see a different number of
              // paragraphs, but nothing bad will happen.
              const ins = (!sanitize && typeof op.insert === 'string' && i === delta.length - 1 && currPos.right === null && op.insert.slice(-1) === '\n') ? op.insert.slice(0, -1) : op.insert;
              if (typeof ins !== 'string' || ins.length > 0) {
                insertText(transaction, this, currPos, ins, op.attributes || {});
              }
            } else if (op.retain !== undefined) {
              formatText(transaction, this, currPos, op.retain, op.attributes || {});
            } else if (op.delete !== undefined) {
              deleteText(transaction, currPos, op.delete);
            }
          }
        });
      } else {
        /** @type {Array<function>} */ (this._pending).push(() => this.applyDelta(delta));
      }
    }

    /**
     * Returns the Delta representation of this YText type.
     *
     * @param {Snapshot} [snapshot]
     * @param {Snapshot} [prevSnapshot]
     * @param {function('removed' | 'added', ID):any} [computeYChange]
     * @return {any} The Delta representation of this type.
     *
     * @public
     */
    toDelta (snapshot, prevSnapshot, computeYChange) {
      /**
       * @type{Array<any>}
       */
      const ops = [];
      const currentAttributes = new Map();
      const doc = /** @type {Doc} */ (this.doc);
      let str = '';
      let n = this._start;
      function packStr () {
        if (str.length > 0) {
          // pack str with attributes to ops
          /**
           * @type {Object<string,any>}
           */
          const attributes = {};
          let addAttributes = false;
          currentAttributes.forEach((value, key) => {
            addAttributes = true;
            attributes[key] = value;
          });
          /**
           * @type {Object<string,any>}
           */
          const op = { insert: str };
          if (addAttributes) {
            op.attributes = attributes;
          }
          ops.push(op);
          str = '';
        }
      }
      const computeDelta = () => {
        while (n !== null) {
          if (isVisible(n, snapshot) || (prevSnapshot !== undefined && isVisible(n, prevSnapshot))) {
            switch (n.content.constructor) {
              case ContentString: {
                const cur = currentAttributes.get('ychange');
                if (snapshot !== undefined && !isVisible(n, snapshot)) {
                  if (cur === undefined || cur.user !== n.id.client || cur.type !== 'removed') {
                    packStr();
                    currentAttributes.set('ychange', computeYChange ? computeYChange('removed', n.id) : { type: 'removed' });
                  }
                } else if (prevSnapshot !== undefined && !isVisible(n, prevSnapshot)) {
                  if (cur === undefined || cur.user !== n.id.client || cur.type !== 'added') {
                    packStr();
                    currentAttributes.set('ychange', computeYChange ? computeYChange('added', n.id) : { type: 'added' });
                  }
                } else if (cur !== undefined) {
                  packStr();
                  currentAttributes.delete('ychange');
                }
                str += /** @type {ContentString} */ (n.content).str;
                break
              }
              case ContentType:
              case ContentEmbed: {
                packStr();
                /**
                 * @type {Object<string,any>}
                 */
                const op = {
                  insert: n.content.getContent()[0]
                };
                if (currentAttributes.size > 0) {
                  const attrs = /** @type {Object<string,any>} */ ({});
                  op.attributes = attrs;
                  currentAttributes.forEach((value, key) => {
                    attrs[key] = value;
                  });
                }
                ops.push(op);
                break
              }
              case ContentFormat:
                if (isVisible(n, snapshot)) {
                  packStr();
                  updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (n.content));
                }
                break
            }
          }
          n = n.right;
        }
        packStr();
      };
      if (snapshot || prevSnapshot) {
        // snapshots are merged again after the transaction, so we need to keep the
        // transaction alive until we are done
        transact(doc, transaction => {
          if (snapshot) {
            splitSnapshotAffectedStructs(transaction, snapshot);
          }
          if (prevSnapshot) {
            splitSnapshotAffectedStructs(transaction, prevSnapshot);
          }
          computeDelta();
        }, 'cleanup');
      } else {
        computeDelta();
      }
      return ops
    }

    /**
     * Insert text at a given index.
     *
     * @param {number} index The index at which to start inserting.
     * @param {String} text The text to insert at the specified position.
     * @param {TextAttributes} [attributes] Optionally define some formatting
     *                                    information to apply on the inserted
     *                                    Text.
     * @public
     */
    insert (index, text, attributes) {
      if (text.length <= 0) {
        return
      }
      const y = this.doc;
      if (y !== null) {
        transact(y, transaction => {
          const pos = findPosition(transaction, this, index);
          if (!attributes) {
            attributes = {};
            // @ts-ignore
            pos.currentAttributes.forEach((v, k) => { attributes[k] = v; });
          }
          insertText(transaction, this, pos, text, attributes);
        });
      } else {
        /** @type {Array<function>} */ (this._pending).push(() => this.insert(index, text, attributes));
      }
    }

    /**
     * Inserts an embed at a index.
     *
     * @param {number} index The index to insert the embed at.
     * @param {Object | AbstractType<any>} embed The Object that represents the embed.
     * @param {TextAttributes} attributes Attribute information to apply on the
     *                                    embed
     *
     * @public
     */
    insertEmbed (index, embed, attributes = {}) {
      const y = this.doc;
      if (y !== null) {
        transact(y, transaction => {
          const pos = findPosition(transaction, this, index);
          insertText(transaction, this, pos, embed, attributes);
        });
      } else {
        /** @type {Array<function>} */ (this._pending).push(() => this.insertEmbed(index, embed, attributes));
      }
    }

    /**
     * Deletes text starting from an index.
     *
     * @param {number} index Index at which to start deleting.
     * @param {number} length The number of characters to remove. Defaults to 1.
     *
     * @public
     */
    delete (index, length) {
      if (length === 0) {
        return
      }
      const y = this.doc;
      if (y !== null) {
        transact(y, transaction => {
          deleteText(transaction, findPosition(transaction, this, index), length);
        });
      } else {
        /** @type {Array<function>} */ (this._pending).push(() => this.delete(index, length));
      }
    }

    /**
     * Assigns properties to a range of text.
     *
     * @param {number} index The position where to start formatting.
     * @param {number} length The amount of characters to assign properties to.
     * @param {TextAttributes} attributes Attribute information to apply on the
     *                                    text.
     *
     * @public
     */
    format (index, length, attributes) {
      if (length === 0) {
        return
      }
      const y = this.doc;
      if (y !== null) {
        transact(y, transaction => {
          const pos = findPosition(transaction, this, index);
          if (pos.right === null) {
            return
          }
          formatText(transaction, this, pos, length, attributes);
        });
      } else {
        /** @type {Array<function>} */ (this._pending).push(() => this.format(index, length, attributes));
      }
    }

    /**
     * Removes an attribute.
     *
     * @note Xml-Text nodes don't have attributes. You can use this feature to assign properties to complete text-blocks.
     *
     * @param {String} attributeName The attribute name that is to be removed.
     *
     * @public
     */
    removeAttribute (attributeName) {
      if (this.doc !== null) {
        transact(this.doc, transaction => {
          typeMapDelete(transaction, this, attributeName);
        });
      } else {
        /** @type {Array<function>} */ (this._pending).push(() => this.removeAttribute(attributeName));
      }
    }

    /**
     * Sets or updates an attribute.
     *
     * @note Xml-Text nodes don't have attributes. You can use this feature to assign properties to complete text-blocks.
     *
     * @param {String} attributeName The attribute name that is to be set.
     * @param {any} attributeValue The attribute value that is to be set.
     *
     * @public
     */
    setAttribute (attributeName, attributeValue) {
      if (this.doc !== null) {
        transact(this.doc, transaction => {
          typeMapSet(transaction, this, attributeName, attributeValue);
        });
      } else {
        /** @type {Array<function>} */ (this._pending).push(() => this.setAttribute(attributeName, attributeValue));
      }
    }

    /**
     * Returns an attribute value that belongs to the attribute name.
     *
     * @note Xml-Text nodes don't have attributes. You can use this feature to assign properties to complete text-blocks.
     *
     * @param {String} attributeName The attribute name that identifies the
     *                               queried value.
     * @return {any} The queried attribute value.
     *
     * @public
     */
    getAttribute (attributeName) {
      return /** @type {any} */ (typeMapGet(this, attributeName))
    }

    /**
     * Returns all attribute name/value pairs in a JSON Object.
     *
     * @note Xml-Text nodes don't have attributes. You can use this feature to assign properties to complete text-blocks.
     *
     * @return {Object<string, any>} A JSON Object that describes the attributes.
     *
     * @public
     */
    getAttributes () {
      return typeMapGetAll(this)
    }

    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
     */
    _write (encoder) {
      encoder.writeTypeRef(YTextRefID);
    }
  }

  /**
   * @module YXml
   */

  /**
   * Define the elements to which a set of CSS queries apply.
   * {@link https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Selectors|CSS_Selectors}
   *
   * @example
   *   query = '.classSelector'
   *   query = 'nodeSelector'
   *   query = '#idSelector'
   *
   * @typedef {string} CSS_Selector
   */

  /**
   * Dom filter function.
   *
   * @callback domFilter
   * @param {string} nodeName The nodeName of the element
   * @param {Map} attributes The map of attributes.
   * @return {boolean} Whether to include the Dom node in the YXmlElement.
   */

  /**
   * Represents a subset of the nodes of a YXmlElement / YXmlFragment and a
   * position within them.
   *
   * Can be created with {@link YXmlFragment#createTreeWalker}
   *
   * @public
   * @implements {Iterable<YXmlElement|YXmlText|YXmlElement|YXmlHook>}
   */
  class YXmlTreeWalker {
    /**
     * @param {YXmlFragment | YXmlElement} root
     * @param {function(AbstractType<any>):boolean} [f]
     */
    constructor (root, f = () => true) {
      this._filter = f;
      this._root = root;
      /**
       * @type {Item}
       */
      this._currentNode = /** @type {Item} */ (root._start);
      this._firstCall = true;
    }

    [Symbol.iterator] () {
      return this
    }

    /**
     * Get the next node.
     *
     * @return {IteratorResult<YXmlElement|YXmlText|YXmlHook>} The next node.
     *
     * @public
     */
    next () {
      /**
       * @type {Item|null}
       */
      let n = this._currentNode;
      let type = n && n.content && /** @type {any} */ (n.content).type;
      if (n !== null && (!this._firstCall || n.deleted || !this._filter(type))) { // if first call, we check if we can use the first item
        do {
          type = /** @type {any} */ (n.content).type;
          if (!n.deleted && (type.constructor === YXmlElement || type.constructor === YXmlFragment) && type._start !== null) {
            // walk down in the tree
            n = type._start;
          } else {
            // walk right or up in the tree
            while (n !== null) {
              if (n.right !== null) {
                n = n.right;
                break
              } else if (n.parent === this._root) {
                n = null;
              } else {
                n = /** @type {AbstractType<any>} */ (n.parent)._item;
              }
            }
          }
        } while (n !== null && (n.deleted || !this._filter(/** @type {ContentType} */ (n.content).type)))
      }
      this._firstCall = false;
      if (n === null) {
        // @ts-ignore
        return { value: undefined, done: true }
      }
      this._currentNode = n;
      return { value: /** @type {any} */ (n.content).type, done: false }
    }
  }

  /**
   * Represents a list of {@link YXmlElement}.and {@link YXmlText} types.
   * A YxmlFragment is similar to a {@link YXmlElement}, but it does not have a
   * nodeName and it does not have attributes. Though it can be bound to a DOM
   * element - in this case the attributes and the nodeName are not shared.
   *
   * @public
   * @extends AbstractType<YXmlEvent>
   */
  class YXmlFragment extends AbstractType {
    constructor () {
      super();
      /**
       * @type {Array<any>|null}
       */
      this._prelimContent = [];
    }

    /**
     * @type {YXmlElement|YXmlText|null}
     */
    get firstChild () {
      const first = this._first;
      return first ? first.content.getContent()[0] : null
    }

    /**
     * Integrate this type into the Yjs instance.
     *
     * * Save this struct in the os
     * * This type is sent to other client
     * * Observer functions are fired
     *
     * @param {Doc} y The Yjs instance
     * @param {Item} item
     */
    _integrate (y, item) {
      super._integrate(y, item);
      this.insert(0, /** @type {Array<any>} */ (this._prelimContent));
      this._prelimContent = null;
    }

    _copy () {
      return new YXmlFragment()
    }

    /**
     * @return {YXmlFragment}
     */
    clone () {
      const el = new YXmlFragment();
      // @ts-ignore
      el.insert(0, this.toArray().map(item => item instanceof AbstractType ? item.clone() : item));
      return el
    }

    get length () {
      return this._prelimContent === null ? this._length : this._prelimContent.length
    }

    /**
     * Create a subtree of childNodes.
     *
     * @example
     * const walker = elem.createTreeWalker(dom => dom.nodeName === 'div')
     * for (let node in walker) {
     *   // `node` is a div node
     *   nop(node)
     * }
     *
     * @param {function(AbstractType<any>):boolean} filter Function that is called on each child element and
     *                          returns a Boolean indicating whether the child
     *                          is to be included in the subtree.
     * @return {YXmlTreeWalker} A subtree and a position within it.
     *
     * @public
     */
    createTreeWalker (filter) {
      return new YXmlTreeWalker(this, filter)
    }

    /**
     * Returns the first YXmlElement that matches the query.
     * Similar to DOM's {@link querySelector}.
     *
     * Query support:
     *   - tagname
     * TODO:
     *   - id
     *   - attribute
     *
     * @param {CSS_Selector} query The query on the children.
     * @return {YXmlElement|YXmlText|YXmlHook|null} The first element that matches the query or null.
     *
     * @public
     */
    querySelector (query) {
      query = query.toUpperCase();
      // @ts-ignore
      const iterator = new YXmlTreeWalker(this, element => element.nodeName && element.nodeName.toUpperCase() === query);
      const next = iterator.next();
      if (next.done) {
        return null
      } else {
        return next.value
      }
    }

    /**
     * Returns all YXmlElements that match the query.
     * Similar to Dom's {@link querySelectorAll}.
     *
     * @todo Does not yet support all queries. Currently only query by tagName.
     *
     * @param {CSS_Selector} query The query on the children
     * @return {Array<YXmlElement|YXmlText|YXmlHook|null>} The elements that match this query.
     *
     * @public
     */
    querySelectorAll (query) {
      query = query.toUpperCase();
      // @ts-ignore
      return from(new YXmlTreeWalker(this, element => element.nodeName && element.nodeName.toUpperCase() === query))
    }

    /**
     * Creates YXmlEvent and calls observers.
     *
     * @param {Transaction} transaction
     * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
     */
    _callObserver (transaction, parentSubs) {
      callTypeObservers(this, transaction, new YXmlEvent(this, parentSubs, transaction));
    }

    /**
     * Get the string representation of all the children of this YXmlFragment.
     *
     * @return {string} The string representation of all children.
     */
    toString () {
      return typeListMap(this, xml => xml.toString()).join('')
    }

    /**
     * @return {string}
     */
    toJSON () {
      return this.toString()
    }

    /**
     * Creates a Dom Element that mirrors this YXmlElement.
     *
     * @param {Document} [_document=document] The document object (you must define
     *                                        this when calling this method in
     *                                        nodejs)
     * @param {Object<string, any>} [hooks={}] Optional property to customize how hooks
     *                                             are presented in the DOM
     * @param {any} [binding] You should not set this property. This is
     *                               used if DomBinding wants to create a
     *                               association to the created DOM type.
     * @return {Node} The {@link https://developer.mozilla.org/en-US/docs/Web/API/Element|Dom Element}
     *
     * @public
     */
    toDOM (_document = document, hooks = {}, binding) {
      const fragment = _document.createDocumentFragment();
      if (binding !== undefined) {
        binding._createAssociation(fragment, this);
      }
      typeListForEach(this, xmlType => {
        fragment.insertBefore(xmlType.toDOM(_document, hooks, binding), null);
      });
      return fragment
    }

    /**
     * Inserts new content at an index.
     *
     * @example
     *  // Insert character 'a' at position 0
     *  xml.insert(0, [new Y.XmlText('text')])
     *
     * @param {number} index The index to insert content at
     * @param {Array<YXmlElement|YXmlText>} content The array of content
     */
    insert (index, content) {
      if (this.doc !== null) {
        transact(this.doc, transaction => {
          typeListInsertGenerics(transaction, this, index, content);
        });
      } else {
        // @ts-ignore _prelimContent is defined because this is not yet integrated
        this._prelimContent.splice(index, 0, ...content);
      }
    }

    /**
     * Inserts new content at an index.
     *
     * @example
     *  // Insert character 'a' at position 0
     *  xml.insert(0, [new Y.XmlText('text')])
     *
     * @param {null|Item|YXmlElement|YXmlText} ref The index to insert content at
     * @param {Array<YXmlElement|YXmlText>} content The array of content
     */
    insertAfter (ref, content) {
      if (this.doc !== null) {
        transact(this.doc, transaction => {
          const refItem = (ref && ref instanceof AbstractType) ? ref._item : ref;
          typeListInsertGenericsAfter(transaction, this, refItem, content);
        });
      } else {
        const pc = /** @type {Array<any>} */ (this._prelimContent);
        const index = ref === null ? 0 : pc.findIndex(el => el === ref) + 1;
        if (index === 0 && ref !== null) {
          throw create$2('Reference item not found')
        }
        pc.splice(index, 0, ...content);
      }
    }

    /**
     * Deletes elements starting from an index.
     *
     * @param {number} index Index at which to start deleting elements
     * @param {number} [length=1] The number of elements to remove. Defaults to 1.
     */
    delete (index, length = 1) {
      if (this.doc !== null) {
        transact(this.doc, transaction => {
          typeListDelete(transaction, this, index, length);
        });
      } else {
        // @ts-ignore _prelimContent is defined because this is not yet integrated
        this._prelimContent.splice(index, length);
      }
    }

    /**
     * Transforms this YArray to a JavaScript Array.
     *
     * @return {Array<YXmlElement|YXmlText|YXmlHook>}
     */
    toArray () {
      return typeListToArray(this)
    }

    /**
     * Appends content to this YArray.
     *
     * @param {Array<YXmlElement|YXmlText>} content Array of content to append.
     */
    push (content) {
      this.insert(this.length, content);
    }

    /**
     * Preppends content to this YArray.
     *
     * @param {Array<YXmlElement|YXmlText>} content Array of content to preppend.
     */
    unshift (content) {
      this.insert(0, content);
    }

    /**
     * Returns the i-th element from a YArray.
     *
     * @param {number} index The index of the element to return from the YArray
     * @return {YXmlElement|YXmlText}
     */
    get (index) {
      return typeListGet(this, index)
    }

    /**
     * Transforms this YArray to a JavaScript Array.
     *
     * @param {number} [start]
     * @param {number} [end]
     * @return {Array<YXmlElement|YXmlText>}
     */
    slice (start = 0, end = this.length) {
      return typeListSlice(this, start, end)
    }

    /**
     * Executes a provided function on once on overy child element.
     *
     * @param {function(YXmlElement|YXmlText,number, typeof self):void} f A function to execute on every element of this YArray.
     */
    forEach (f) {
      typeListForEach(this, f);
    }

    /**
     * Transform the properties of this type to binary and write it to an
     * BinaryEncoder.
     *
     * This is called when this Item is sent to a remote peer.
     *
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder The encoder to write data to.
     */
    _write (encoder) {
      encoder.writeTypeRef(YXmlFragmentRefID);
    }
  }

  /**
   * @typedef {Object|number|null|Array<any>|string|Uint8Array|AbstractType<any>} ValueTypes
   */

  /**
   * An YXmlElement imitates the behavior of a
   * {@link https://developer.mozilla.org/en-US/docs/Web/API/Element|Dom Element}.
   *
   * * An YXmlElement has attributes (key value pairs)
   * * An YXmlElement has childElements that must inherit from YXmlElement
   *
   * @template {{ [key: string]: ValueTypes }} [KV={ [key: string]: string }]
   */
  class YXmlElement extends YXmlFragment {
    constructor (nodeName = 'UNDEFINED') {
      super();
      this.nodeName = nodeName;
      /**
       * @type {Map<string, any>|null}
       */
      this._prelimAttrs = new Map();
    }

    /**
     * @type {YXmlElement|YXmlText|null}
     */
    get nextSibling () {
      const n = this._item ? this._item.next : null;
      return n ? /** @type {YXmlElement|YXmlText} */ (/** @type {ContentType} */ (n.content).type) : null
    }

    /**
     * @type {YXmlElement|YXmlText|null}
     */
    get prevSibling () {
      const n = this._item ? this._item.prev : null;
      return n ? /** @type {YXmlElement|YXmlText} */ (/** @type {ContentType} */ (n.content).type) : null
    }

    /**
     * Integrate this type into the Yjs instance.
     *
     * * Save this struct in the os
     * * This type is sent to other client
     * * Observer functions are fired
     *
     * @param {Doc} y The Yjs instance
     * @param {Item} item
     */
    _integrate (y, item) {
      super._integrate(y, item)
      ;(/** @type {Map<string, any>} */ (this._prelimAttrs)).forEach((value, key) => {
        this.setAttribute(key, value);
      });
      this._prelimAttrs = null;
    }

    /**
     * Creates an Item with the same effect as this Item (without position effect)
     *
     * @return {YXmlElement}
     */
    _copy () {
      return new YXmlElement(this.nodeName)
    }

    /**
     * @return {YXmlElement<KV>}
     */
    clone () {
      /**
       * @type {YXmlElement<KV>}
       */
      const el = new YXmlElement(this.nodeName);
      const attrs = this.getAttributes();
      forEach$1(attrs, (value, key) => {
        if (typeof value === 'string') {
          el.setAttribute(key, value);
        }
      });
      // @ts-ignore
      el.insert(0, this.toArray().map(item => item instanceof AbstractType ? item.clone() : item));
      return el
    }

    /**
     * Returns the XML serialization of this YXmlElement.
     * The attributes are ordered by attribute-name, so you can easily use this
     * method to compare YXmlElements
     *
     * @return {string} The string representation of this type.
     *
     * @public
     */
    toString () {
      const attrs = this.getAttributes();
      const stringBuilder = [];
      const keys = [];
      for (const key in attrs) {
        keys.push(key);
      }
      keys.sort();
      const keysLen = keys.length;
      for (let i = 0; i < keysLen; i++) {
        const key = keys[i];
        stringBuilder.push(key + '="' + attrs[key] + '"');
      }
      const nodeName = this.nodeName.toLocaleLowerCase();
      const attrsString = stringBuilder.length > 0 ? ' ' + stringBuilder.join(' ') : '';
      return `<${nodeName}${attrsString}>${super.toString()}</${nodeName}>`
    }

    /**
     * Removes an attribute from this YXmlElement.
     *
     * @param {string} attributeName The attribute name that is to be removed.
     *
     * @public
     */
    removeAttribute (attributeName) {
      if (this.doc !== null) {
        transact(this.doc, transaction => {
          typeMapDelete(transaction, this, attributeName);
        });
      } else {
        /** @type {Map<string,any>} */ (this._prelimAttrs).delete(attributeName);
      }
    }

    /**
     * Sets or updates an attribute.
     *
     * @template {keyof KV & string} KEY
     *
     * @param {KEY} attributeName The attribute name that is to be set.
     * @param {KV[KEY]} attributeValue The attribute value that is to be set.
     *
     * @public
     */
    setAttribute (attributeName, attributeValue) {
      if (this.doc !== null) {
        transact(this.doc, transaction => {
          typeMapSet(transaction, this, attributeName, attributeValue);
        });
      } else {
        /** @type {Map<string, any>} */ (this._prelimAttrs).set(attributeName, attributeValue);
      }
    }

    /**
     * Returns an attribute value that belongs to the attribute name.
     *
     * @template {keyof KV & string} KEY
     *
     * @param {KEY} attributeName The attribute name that identifies the
     *                               queried value.
     * @return {KV[KEY]|undefined} The queried attribute value.
     *
     * @public
     */
    getAttribute (attributeName) {
      return /** @type {any} */ (typeMapGet(this, attributeName))
    }

    /**
     * Returns whether an attribute exists
     *
     * @param {string} attributeName The attribute name to check for existence.
     * @return {boolean} whether the attribute exists.
     *
     * @public
     */
    hasAttribute (attributeName) {
      return /** @type {any} */ (typeMapHas(this, attributeName))
    }

    /**
     * Returns all attribute name/value pairs in a JSON Object.
     *
     * @return {{ [Key in Extract<keyof KV,string>]?: KV[Key]}} A JSON Object that describes the attributes.
     *
     * @public
     */
    getAttributes () {
      return /** @type {any} */ (typeMapGetAll(this))
    }

    /**
     * Creates a Dom Element that mirrors this YXmlElement.
     *
     * @param {Document} [_document=document] The document object (you must define
     *                                        this when calling this method in
     *                                        nodejs)
     * @param {Object<string, any>} [hooks={}] Optional property to customize how hooks
     *                                             are presented in the DOM
     * @param {any} [binding] You should not set this property. This is
     *                               used if DomBinding wants to create a
     *                               association to the created DOM type.
     * @return {Node} The {@link https://developer.mozilla.org/en-US/docs/Web/API/Element|Dom Element}
     *
     * @public
     */
    toDOM (_document = document, hooks = {}, binding) {
      const dom = _document.createElement(this.nodeName);
      const attrs = this.getAttributes();
      for (const key in attrs) {
        const value = attrs[key];
        if (typeof value === 'string') {
          dom.setAttribute(key, value);
        }
      }
      typeListForEach(this, yxml => {
        dom.appendChild(yxml.toDOM(_document, hooks, binding));
      });
      if (binding !== undefined) {
        binding._createAssociation(dom, this);
      }
      return dom
    }

    /**
     * Transform the properties of this type to binary and write it to an
     * BinaryEncoder.
     *
     * This is called when this Item is sent to a remote peer.
     *
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder The encoder to write data to.
     */
    _write (encoder) {
      encoder.writeTypeRef(YXmlElementRefID);
      encoder.writeKey(this.nodeName);
    }
  }

  /**
   * @extends YEvent<YXmlElement|YXmlText|YXmlFragment>
   * An Event that describes changes on a YXml Element or Yxml Fragment
   */
  class YXmlEvent extends YEvent {
    /**
     * @param {YXmlElement|YXmlText|YXmlFragment} target The target on which the event is created.
     * @param {Set<string|null>} subs The set of changed attributes. `null` is included if the
     *                   child list changed.
     * @param {Transaction} transaction The transaction instance with wich the
     *                                  change was created.
     */
    constructor (target, subs, transaction) {
      super(target, transaction);
      /**
       * Whether the children changed.
       * @type {Boolean}
       * @private
       */
      this.childListChanged = false;
      /**
       * Set of all changed attributes.
       * @type {Set<string>}
       */
      this.attributesChanged = new Set();
      subs.forEach((sub) => {
        if (sub === null) {
          this.childListChanged = true;
        } else {
          this.attributesChanged.add(sub);
        }
      });
    }
  }

  class AbstractStruct {
    /**
     * @param {ID} id
     * @param {number} length
     */
    constructor (id, length) {
      this.id = id;
      this.length = length;
    }

    /**
     * @type {boolean}
     */
    get deleted () {
      throw methodUnimplemented()
    }

    /**
     * Merge this struct with the item to the right.
     * This method is already assuming that `this.id.clock + this.length === this.id.clock`.
     * Also this method does *not* remove right from StructStore!
     * @param {AbstractStruct} right
     * @return {boolean} wether this merged with right
     */
    mergeWith (right) {
      return false
    }

    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder The encoder to write data to.
     * @param {number} offset
     * @param {number} encodingRef
     */
    write (encoder, offset, encodingRef) {
      throw methodUnimplemented()
    }

    /**
     * @param {Transaction} transaction
     * @param {number} offset
     */
    integrate (transaction, offset) {
      throw methodUnimplemented()
    }
  }

  const structGCRefNumber = 0;

  /**
   * @private
   */
  class GC extends AbstractStruct {
    get deleted () {
      return true
    }

    delete () {}

    /**
     * @param {GC} right
     * @return {boolean}
     */
    mergeWith (right) {
      if (this.constructor !== right.constructor) {
        return false
      }
      this.length += right.length;
      return true
    }

    /**
     * @param {Transaction} transaction
     * @param {number} offset
     */
    integrate (transaction, offset) {
      if (offset > 0) {
        this.id.clock += offset;
        this.length -= offset;
      }
      addStruct(transaction.doc.store, this);
    }

    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
     * @param {number} offset
     */
    write (encoder, offset) {
      encoder.writeInfo(structGCRefNumber);
      encoder.writeLen(this.length - offset);
    }

    /**
     * @param {Transaction} transaction
     * @param {StructStore} store
     * @return {null | number}
     */
    getMissing (transaction, store) {
      return null
    }
  }

  class ContentBinary {
    /**
     * @param {Uint8Array} content
     */
    constructor (content) {
      this.content = content;
    }

    /**
     * @return {number}
     */
    getLength () {
      return 1
    }

    /**
     * @return {Array<any>}
     */
    getContent () {
      return [this.content]
    }

    /**
     * @return {boolean}
     */
    isCountable () {
      return true
    }

    /**
     * @return {ContentBinary}
     */
    copy () {
      return new ContentBinary(this.content)
    }

    /**
     * @param {number} offset
     * @return {ContentBinary}
     */
    splice (offset) {
      throw methodUnimplemented()
    }

    /**
     * @param {ContentBinary} right
     * @return {boolean}
     */
    mergeWith (right) {
      return false
    }

    /**
     * @param {Transaction} transaction
     * @param {Item} item
     */
    integrate (transaction, item) {}
    /**
     * @param {Transaction} transaction
     */
    delete (transaction) {}
    /**
     * @param {StructStore} store
     */
    gc (store) {}
    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
     * @param {number} offset
     */
    write (encoder, offset) {
      encoder.writeBuf(this.content);
    }

    /**
     * @return {number}
     */
    getRef () {
      return 3
    }
  }

  class ContentDeleted {
    /**
     * @param {number} len
     */
    constructor (len) {
      this.len = len;
    }

    /**
     * @return {number}
     */
    getLength () {
      return this.len
    }

    /**
     * @return {Array<any>}
     */
    getContent () {
      return []
    }

    /**
     * @return {boolean}
     */
    isCountable () {
      return false
    }

    /**
     * @return {ContentDeleted}
     */
    copy () {
      return new ContentDeleted(this.len)
    }

    /**
     * @param {number} offset
     * @return {ContentDeleted}
     */
    splice (offset) {
      const right = new ContentDeleted(this.len - offset);
      this.len = offset;
      return right
    }

    /**
     * @param {ContentDeleted} right
     * @return {boolean}
     */
    mergeWith (right) {
      this.len += right.len;
      return true
    }

    /**
     * @param {Transaction} transaction
     * @param {Item} item
     */
    integrate (transaction, item) {
      addToDeleteSet(transaction.deleteSet, item.id.client, item.id.clock, this.len);
      item.markDeleted();
    }

    /**
     * @param {Transaction} transaction
     */
    delete (transaction) {}
    /**
     * @param {StructStore} store
     */
    gc (store) {}
    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
     * @param {number} offset
     */
    write (encoder, offset) {
      encoder.writeLen(this.len - offset);
    }

    /**
     * @return {number}
     */
    getRef () {
      return 1
    }
  }

  /**
   * @param {string} guid
   * @param {Object<string, any>} opts
   */
  const createDocFromOpts = (guid, opts) => new Doc({ guid, ...opts, shouldLoad: opts.shouldLoad || opts.autoLoad || false });

  /**
   * @private
   */
  class ContentDoc {
    /**
     * @param {Doc} doc
     */
    constructor (doc) {
      if (doc._item) {
        console.error('This document was already integrated as a sub-document. You should create a second instance instead with the same guid.');
      }
      /**
       * @type {Doc}
       */
      this.doc = doc;
      /**
       * @type {any}
       */
      const opts = {};
      this.opts = opts;
      if (!doc.gc) {
        opts.gc = false;
      }
      if (doc.autoLoad) {
        opts.autoLoad = true;
      }
      if (doc.meta !== null) {
        opts.meta = doc.meta;
      }
    }

    /**
     * @return {number}
     */
    getLength () {
      return 1
    }

    /**
     * @return {Array<any>}
     */
    getContent () {
      return [this.doc]
    }

    /**
     * @return {boolean}
     */
    isCountable () {
      return true
    }

    /**
     * @return {ContentDoc}
     */
    copy () {
      return new ContentDoc(createDocFromOpts(this.doc.guid, this.opts))
    }

    /**
     * @param {number} offset
     * @return {ContentDoc}
     */
    splice (offset) {
      throw methodUnimplemented()
    }

    /**
     * @param {ContentDoc} right
     * @return {boolean}
     */
    mergeWith (right) {
      return false
    }

    /**
     * @param {Transaction} transaction
     * @param {Item} item
     */
    integrate (transaction, item) {
      // this needs to be reflected in doc.destroy as well
      this.doc._item = item;
      transaction.subdocsAdded.add(this.doc);
      if (this.doc.shouldLoad) {
        transaction.subdocsLoaded.add(this.doc);
      }
    }

    /**
     * @param {Transaction} transaction
     */
    delete (transaction) {
      if (transaction.subdocsAdded.has(this.doc)) {
        transaction.subdocsAdded.delete(this.doc);
      } else {
        transaction.subdocsRemoved.add(this.doc);
      }
    }

    /**
     * @param {StructStore} store
     */
    gc (store) { }

    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
     * @param {number} offset
     */
    write (encoder, offset) {
      encoder.writeString(this.doc.guid);
      encoder.writeAny(this.opts);
    }

    /**
     * @return {number}
     */
    getRef () {
      return 9
    }
  }

  /**
   * @private
   */
  class ContentEmbed {
    /**
     * @param {Object} embed
     */
    constructor (embed) {
      this.embed = embed;
    }

    /**
     * @return {number}
     */
    getLength () {
      return 1
    }

    /**
     * @return {Array<any>}
     */
    getContent () {
      return [this.embed]
    }

    /**
     * @return {boolean}
     */
    isCountable () {
      return true
    }

    /**
     * @return {ContentEmbed}
     */
    copy () {
      return new ContentEmbed(this.embed)
    }

    /**
     * @param {number} offset
     * @return {ContentEmbed}
     */
    splice (offset) {
      throw methodUnimplemented()
    }

    /**
     * @param {ContentEmbed} right
     * @return {boolean}
     */
    mergeWith (right) {
      return false
    }

    /**
     * @param {Transaction} transaction
     * @param {Item} item
     */
    integrate (transaction, item) {}
    /**
     * @param {Transaction} transaction
     */
    delete (transaction) {}
    /**
     * @param {StructStore} store
     */
    gc (store) {}
    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
     * @param {number} offset
     */
    write (encoder, offset) {
      encoder.writeJSON(this.embed);
    }

    /**
     * @return {number}
     */
    getRef () {
      return 5
    }
  }

  /**
   * @private
   */
  class ContentFormat {
    /**
     * @param {string} key
     * @param {Object} value
     */
    constructor (key, value) {
      this.key = key;
      this.value = value;
    }

    /**
     * @return {number}
     */
    getLength () {
      return 1
    }

    /**
     * @return {Array<any>}
     */
    getContent () {
      return []
    }

    /**
     * @return {boolean}
     */
    isCountable () {
      return false
    }

    /**
     * @return {ContentFormat}
     */
    copy () {
      return new ContentFormat(this.key, this.value)
    }

    /**
     * @param {number} _offset
     * @return {ContentFormat}
     */
    splice (_offset) {
      throw methodUnimplemented()
    }

    /**
     * @param {ContentFormat} _right
     * @return {boolean}
     */
    mergeWith (_right) {
      return false
    }

    /**
     * @param {Transaction} _transaction
     * @param {Item} item
     */
    integrate (_transaction, item) {
      // @todo searchmarker are currently unsupported for rich text documents
      const p = /** @type {YText} */ (item.parent);
      p._searchMarker = null;
      p._hasFormatting = true;
    }

    /**
     * @param {Transaction} transaction
     */
    delete (transaction) {}
    /**
     * @param {StructStore} store
     */
    gc (store) {}
    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
     * @param {number} offset
     */
    write (encoder, offset) {
      encoder.writeKey(this.key);
      encoder.writeJSON(this.value);
    }

    /**
     * @return {number}
     */
    getRef () {
      return 6
    }
  }

  class ContentAny {
    /**
     * @param {Array<any>} arr
     */
    constructor (arr) {
      /**
       * @type {Array<any>}
       */
      this.arr = arr;
    }

    /**
     * @return {number}
     */
    getLength () {
      return this.arr.length
    }

    /**
     * @return {Array<any>}
     */
    getContent () {
      return this.arr
    }

    /**
     * @return {boolean}
     */
    isCountable () {
      return true
    }

    /**
     * @return {ContentAny}
     */
    copy () {
      return new ContentAny(this.arr)
    }

    /**
     * @param {number} offset
     * @return {ContentAny}
     */
    splice (offset) {
      const right = new ContentAny(this.arr.slice(offset));
      this.arr = this.arr.slice(0, offset);
      return right
    }

    /**
     * @param {ContentAny} right
     * @return {boolean}
     */
    mergeWith (right) {
      this.arr = this.arr.concat(right.arr);
      return true
    }

    /**
     * @param {Transaction} transaction
     * @param {Item} item
     */
    integrate (transaction, item) {}
    /**
     * @param {Transaction} transaction
     */
    delete (transaction) {}
    /**
     * @param {StructStore} store
     */
    gc (store) {}
    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
     * @param {number} offset
     */
    write (encoder, offset) {
      const len = this.arr.length;
      encoder.writeLen(len - offset);
      for (let i = offset; i < len; i++) {
        const c = this.arr[i];
        encoder.writeAny(c);
      }
    }

    /**
     * @return {number}
     */
    getRef () {
      return 8
    }
  }

  /**
   * @private
   */
  class ContentString {
    /**
     * @param {string} str
     */
    constructor (str) {
      /**
       * @type {string}
       */
      this.str = str;
    }

    /**
     * @return {number}
     */
    getLength () {
      return this.str.length
    }

    /**
     * @return {Array<any>}
     */
    getContent () {
      return this.str.split('')
    }

    /**
     * @return {boolean}
     */
    isCountable () {
      return true
    }

    /**
     * @return {ContentString}
     */
    copy () {
      return new ContentString(this.str)
    }

    /**
     * @param {number} offset
     * @return {ContentString}
     */
    splice (offset) {
      const right = new ContentString(this.str.slice(offset));
      this.str = this.str.slice(0, offset);

      // Prevent encoding invalid documents because of splitting of surrogate pairs: https://github.com/yjs/yjs/issues/248
      const firstCharCode = this.str.charCodeAt(offset - 1);
      if (firstCharCode >= 0xD800 && firstCharCode <= 0xDBFF) {
        // Last character of the left split is the start of a surrogate utf16/ucs2 pair.
        // We don't support splitting of surrogate pairs because this may lead to invalid documents.
        // Replace the invalid character with a unicode replacement character (� / U+FFFD)
        this.str = this.str.slice(0, offset - 1) + '�';
        // replace right as well
        right.str = '�' + right.str.slice(1);
      }
      return right
    }

    /**
     * @param {ContentString} right
     * @return {boolean}
     */
    mergeWith (right) {
      this.str += right.str;
      return true
    }

    /**
     * @param {Transaction} transaction
     * @param {Item} item
     */
    integrate (transaction, item) {}
    /**
     * @param {Transaction} transaction
     */
    delete (transaction) {}
    /**
     * @param {StructStore} store
     */
    gc (store) {}
    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
     * @param {number} offset
     */
    write (encoder, offset) {
      encoder.writeString(offset === 0 ? this.str : this.str.slice(offset));
    }

    /**
     * @return {number}
     */
    getRef () {
      return 4
    }
  }

  const YArrayRefID = 0;
  const YMapRefID = 1;
  const YTextRefID = 2;
  const YXmlElementRefID = 3;
  const YXmlFragmentRefID = 4;

  /**
   * @private
   */
  class ContentType {
    /**
     * @param {AbstractType<any>} type
     */
    constructor (type) {
      /**
       * @type {AbstractType<any>}
       */
      this.type = type;
    }

    /**
     * @return {number}
     */
    getLength () {
      return 1
    }

    /**
     * @return {Array<any>}
     */
    getContent () {
      return [this.type]
    }

    /**
     * @return {boolean}
     */
    isCountable () {
      return true
    }

    /**
     * @return {ContentType}
     */
    copy () {
      return new ContentType(this.type._copy())
    }

    /**
     * @param {number} offset
     * @return {ContentType}
     */
    splice (offset) {
      throw methodUnimplemented()
    }

    /**
     * @param {ContentType} right
     * @return {boolean}
     */
    mergeWith (right) {
      return false
    }

    /**
     * @param {Transaction} transaction
     * @param {Item} item
     */
    integrate (transaction, item) {
      this.type._integrate(transaction.doc, item);
    }

    /**
     * @param {Transaction} transaction
     */
    delete (transaction) {
      let item = this.type._start;
      while (item !== null) {
        if (!item.deleted) {
          item.delete(transaction);
        } else if (item.id.clock < (transaction.beforeState.get(item.id.client) || 0)) {
          // This will be gc'd later and we want to merge it if possible
          // We try to merge all deleted items after each transaction,
          // but we have no knowledge about that this needs to be merged
          // since it is not in transaction.ds. Hence we add it to transaction._mergeStructs
          transaction._mergeStructs.push(item);
        }
        item = item.right;
      }
      this.type._map.forEach(item => {
        if (!item.deleted) {
          item.delete(transaction);
        } else if (item.id.clock < (transaction.beforeState.get(item.id.client) || 0)) {
          // same as above
          transaction._mergeStructs.push(item);
        }
      });
      transaction.changed.delete(this.type);
    }

    /**
     * @param {StructStore} store
     */
    gc (store) {
      let item = this.type._start;
      while (item !== null) {
        item.gc(store, true);
        item = item.right;
      }
      this.type._start = null;
      this.type._map.forEach(/** @param {Item | null} item */ (item) => {
        while (item !== null) {
          item.gc(store, true);
          item = item.left;
        }
      });
      this.type._map = new Map();
    }

    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
     * @param {number} offset
     */
    write (encoder, offset) {
      this.type._write(encoder);
    }

    /**
     * @return {number}
     */
    getRef () {
      return 7
    }
  }

  /**
   * Split leftItem into two items
   * @param {Transaction} transaction
   * @param {Item} leftItem
   * @param {number} diff
   * @return {Item}
   *
   * @function
   * @private
   */
  const splitItem = (transaction, leftItem, diff) => {
    // create rightItem
    const { client, clock } = leftItem.id;
    const rightItem = new Item(
      createID(client, clock + diff),
      leftItem,
      createID(client, clock + diff - 1),
      leftItem.right,
      leftItem.rightOrigin,
      leftItem.parent,
      leftItem.parentSub,
      leftItem.content.splice(diff)
    );
    if (leftItem.deleted) {
      rightItem.markDeleted();
    }
    if (leftItem.keep) {
      rightItem.keep = true;
    }
    if (leftItem.redone !== null) {
      rightItem.redone = createID(leftItem.redone.client, leftItem.redone.clock + diff);
    }
    // update left (do not set leftItem.rightOrigin as it will lead to problems when syncing)
    leftItem.right = rightItem;
    // update right
    if (rightItem.right !== null) {
      rightItem.right.left = rightItem;
    }
    // right is more specific.
    transaction._mergeStructs.push(rightItem);
    // update parent._map
    if (rightItem.parentSub !== null && rightItem.right === null) {
      /** @type {AbstractType<any>} */ (rightItem.parent)._map.set(rightItem.parentSub, rightItem);
    }
    leftItem.length = diff;
    return rightItem
  };

  /**
   * Abstract class that represents any content.
   */
  class Item extends AbstractStruct {
    /**
     * @param {ID} id
     * @param {Item | null} left
     * @param {ID | null} origin
     * @param {Item | null} right
     * @param {ID | null} rightOrigin
     * @param {AbstractType<any>|ID|null} parent Is a type if integrated, is null if it is possible to copy parent from left or right, is ID before integration to search for it.
     * @param {string | null} parentSub
     * @param {AbstractContent} content
     */
    constructor (id, left, origin, right, rightOrigin, parent, parentSub, content) {
      super(id, content.getLength());
      /**
       * The item that was originally to the left of this item.
       * @type {ID | null}
       */
      this.origin = origin;
      /**
       * The item that is currently to the left of this item.
       * @type {Item | null}
       */
      this.left = left;
      /**
       * The item that is currently to the right of this item.
       * @type {Item | null}
       */
      this.right = right;
      /**
       * The item that was originally to the right of this item.
       * @type {ID | null}
       */
      this.rightOrigin = rightOrigin;
      /**
       * @type {AbstractType<any>|ID|null}
       */
      this.parent = parent;
      /**
       * If the parent refers to this item with some kind of key (e.g. YMap, the
       * key is specified here. The key is then used to refer to the list in which
       * to insert this item. If `parentSub = null` type._start is the list in
       * which to insert to. Otherwise it is `parent._map`.
       * @type {String | null}
       */
      this.parentSub = parentSub;
      /**
       * If this type's effect is redone this type refers to the type that undid
       * this operation.
       * @type {ID | null}
       */
      this.redone = null;
      /**
       * @type {AbstractContent}
       */
      this.content = content;
      /**
       * bit1: keep
       * bit2: countable
       * bit3: deleted
       * bit4: mark - mark node as fast-search-marker
       * @type {number} byte
       */
      this.info = this.content.isCountable() ? BIT2 : 0;
    }

    /**
     * This is used to mark the item as an indexed fast-search marker
     *
     * @type {boolean}
     */
    set marker (isMarked) {
      if (((this.info & BIT4) > 0) !== isMarked) {
        this.info ^= BIT4;
      }
    }

    get marker () {
      return (this.info & BIT4) > 0
    }

    /**
     * If true, do not garbage collect this Item.
     */
    get keep () {
      return (this.info & BIT1) > 0
    }

    set keep (doKeep) {
      if (this.keep !== doKeep) {
        this.info ^= BIT1;
      }
    }

    get countable () {
      return (this.info & BIT2) > 0
    }

    /**
     * Whether this item was deleted or not.
     * @type {Boolean}
     */
    get deleted () {
      return (this.info & BIT3) > 0
    }

    set deleted (doDelete) {
      if (this.deleted !== doDelete) {
        this.info ^= BIT3;
      }
    }

    markDeleted () {
      this.info |= BIT3;
    }

    /**
     * Return the creator clientID of the missing op or define missing items and return null.
     *
     * @param {Transaction} transaction
     * @param {StructStore} store
     * @return {null | number}
     */
    getMissing (transaction, store) {
      if (this.origin && this.origin.client !== this.id.client && this.origin.clock >= getState(store, this.origin.client)) {
        return this.origin.client
      }
      if (this.rightOrigin && this.rightOrigin.client !== this.id.client && this.rightOrigin.clock >= getState(store, this.rightOrigin.client)) {
        return this.rightOrigin.client
      }
      if (this.parent && this.parent.constructor === ID && this.id.client !== this.parent.client && this.parent.clock >= getState(store, this.parent.client)) {
        return this.parent.client
      }

      // We have all missing ids, now find the items

      if (this.origin) {
        this.left = getItemCleanEnd(transaction, store, this.origin);
        this.origin = this.left.lastId;
      }
      if (this.rightOrigin) {
        this.right = getItemCleanStart(transaction, this.rightOrigin);
        this.rightOrigin = this.right.id;
      }
      if ((this.left && this.left.constructor === GC) || (this.right && this.right.constructor === GC)) {
        this.parent = null;
      }
      // only set parent if this shouldn't be garbage collected
      if (!this.parent) {
        if (this.left && this.left.constructor === Item) {
          this.parent = this.left.parent;
          this.parentSub = this.left.parentSub;
        }
        if (this.right && this.right.constructor === Item) {
          this.parent = this.right.parent;
          this.parentSub = this.right.parentSub;
        }
      } else if (this.parent.constructor === ID) {
        const parentItem = getItem(store, this.parent);
        if (parentItem.constructor === GC) {
          this.parent = null;
        } else {
          this.parent = /** @type {ContentType} */ (parentItem.content).type;
        }
      }
      return null
    }

    /**
     * @param {Transaction} transaction
     * @param {number} offset
     */
    integrate (transaction, offset) {
      if (offset > 0) {
        this.id.clock += offset;
        this.left = getItemCleanEnd(transaction, transaction.doc.store, createID(this.id.client, this.id.clock - 1));
        this.origin = this.left.lastId;
        this.content = this.content.splice(offset);
        this.length -= offset;
      }

      if (this.parent) {
        if ((!this.left && (!this.right || this.right.left !== null)) || (this.left && this.left.right !== this.right)) {
          /**
           * @type {Item|null}
           */
          let left = this.left;

          /**
           * @type {Item|null}
           */
          let o;
          // set o to the first conflicting item
          if (left !== null) {
            o = left.right;
          } else if (this.parentSub !== null) {
            o = /** @type {AbstractType<any>} */ (this.parent)._map.get(this.parentSub) || null;
            while (o !== null && o.left !== null) {
              o = o.left;
            }
          } else {
            o = /** @type {AbstractType<any>} */ (this.parent)._start;
          }
          // TODO: use something like DeleteSet here (a tree implementation would be best)
          // @todo use global set definitions
          /**
           * @type {Set<Item>}
           */
          const conflictingItems = new Set();
          /**
           * @type {Set<Item>}
           */
          const itemsBeforeOrigin = new Set();
          // Let c in conflictingItems, b in itemsBeforeOrigin
          // ***{origin}bbbb{this}{c,b}{c,b}{o}***
          // Note that conflictingItems is a subset of itemsBeforeOrigin
          while (o !== null && o !== this.right) {
            itemsBeforeOrigin.add(o);
            conflictingItems.add(o);
            if (compareIDs(this.origin, o.origin)) {
              // case 1
              if (o.id.client < this.id.client) {
                left = o;
                conflictingItems.clear();
              } else if (compareIDs(this.rightOrigin, o.rightOrigin)) {
                // this and o are conflicting and point to the same integration points. The id decides which item comes first.
                // Since this is to the left of o, we can break here
                break
              } // else, o might be integrated before an item that this conflicts with. If so, we will find it in the next iterations
            } else if (o.origin !== null && itemsBeforeOrigin.has(getItem(transaction.doc.store, o.origin))) { // use getItem instead of getItemCleanEnd because we don't want / need to split items.
              // case 2
              if (!conflictingItems.has(getItem(transaction.doc.store, o.origin))) {
                left = o;
                conflictingItems.clear();
              }
            } else {
              break
            }
            o = o.right;
          }
          this.left = left;
        }
        // reconnect left/right + update parent map/start if necessary
        if (this.left !== null) {
          const right = this.left.right;
          this.right = right;
          this.left.right = this;
        } else {
          let r;
          if (this.parentSub !== null) {
            r = /** @type {AbstractType<any>} */ (this.parent)._map.get(this.parentSub) || null;
            while (r !== null && r.left !== null) {
              r = r.left;
            }
          } else {
            r = /** @type {AbstractType<any>} */ (this.parent)._start
            ;/** @type {AbstractType<any>} */ (this.parent)._start = this;
          }
          this.right = r;
        }
        if (this.right !== null) {
          this.right.left = this;
        } else if (this.parentSub !== null) {
          // set as current parent value if right === null and this is parentSub
          /** @type {AbstractType<any>} */ (this.parent)._map.set(this.parentSub, this);
          if (this.left !== null) {
            // this is the current attribute value of parent. delete right
            this.left.delete(transaction);
          }
        }
        // adjust length of parent
        if (this.parentSub === null && this.countable && !this.deleted) {
          /** @type {AbstractType<any>} */ (this.parent)._length += this.length;
        }
        addStruct(transaction.doc.store, this);
        this.content.integrate(transaction, this);
        // add parent to transaction.changed
        addChangedTypeToTransaction(transaction, /** @type {AbstractType<any>} */ (this.parent), this.parentSub);
        if ((/** @type {AbstractType<any>} */ (this.parent)._item !== null && /** @type {AbstractType<any>} */ (this.parent)._item.deleted) || (this.parentSub !== null && this.right !== null)) {
          // delete if parent is deleted or if this is not the current attribute value of parent
          this.delete(transaction);
        }
      } else {
        // parent is not defined. Integrate GC struct instead
        new GC(this.id, this.length).integrate(transaction, 0);
      }
    }

    /**
     * Returns the next non-deleted item
     */
    get next () {
      let n = this.right;
      while (n !== null && n.deleted) {
        n = n.right;
      }
      return n
    }

    /**
     * Returns the previous non-deleted item
     */
    get prev () {
      let n = this.left;
      while (n !== null && n.deleted) {
        n = n.left;
      }
      return n
    }

    /**
     * Computes the last content address of this Item.
     */
    get lastId () {
      // allocating ids is pretty costly because of the amount of ids created, so we try to reuse whenever possible
      return this.length === 1 ? this.id : createID(this.id.client, this.id.clock + this.length - 1)
    }

    /**
     * Try to merge two items
     *
     * @param {Item} right
     * @return {boolean}
     */
    mergeWith (right) {
      if (
        this.constructor === right.constructor &&
        compareIDs(right.origin, this.lastId) &&
        this.right === right &&
        compareIDs(this.rightOrigin, right.rightOrigin) &&
        this.id.client === right.id.client &&
        this.id.clock + this.length === right.id.clock &&
        this.deleted === right.deleted &&
        this.redone === null &&
        right.redone === null &&
        this.content.constructor === right.content.constructor &&
        this.content.mergeWith(right.content)
      ) {
        const searchMarker = /** @type {AbstractType<any>} */ (this.parent)._searchMarker;
        if (searchMarker) {
          searchMarker.forEach(marker => {
            if (marker.p === right) {
              // right is going to be "forgotten" so we need to update the marker
              marker.p = this;
              // adjust marker index
              if (!this.deleted && this.countable) {
                marker.index -= this.length;
              }
            }
          });
        }
        if (right.keep) {
          this.keep = true;
        }
        this.right = right.right;
        if (this.right !== null) {
          this.right.left = this;
        }
        this.length += right.length;
        return true
      }
      return false
    }

    /**
     * Mark this Item as deleted.
     *
     * @param {Transaction} transaction
     */
    delete (transaction) {
      if (!this.deleted) {
        const parent = /** @type {AbstractType<any>} */ (this.parent);
        // adjust the length of parent
        if (this.countable && this.parentSub === null) {
          parent._length -= this.length;
        }
        this.markDeleted();
        addToDeleteSet(transaction.deleteSet, this.id.client, this.id.clock, this.length);
        addChangedTypeToTransaction(transaction, parent, this.parentSub);
        this.content.delete(transaction);
      }
    }

    /**
     * @param {StructStore} store
     * @param {boolean} parentGCd
     */
    gc (store, parentGCd) {
      if (!this.deleted) {
        throw unexpectedCase()
      }
      this.content.gc(store);
      if (parentGCd) {
        replaceStruct(store, this, new GC(this.id, this.length));
      } else {
        this.content = new ContentDeleted(this.length);
      }
    }

    /**
     * Transform the properties of this type to binary and write it to an
     * BinaryEncoder.
     *
     * This is called when this Item is sent to a remote peer.
     *
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder The encoder to write data to.
     * @param {number} offset
     */
    write (encoder, offset) {
      const origin = offset > 0 ? createID(this.id.client, this.id.clock + offset - 1) : this.origin;
      const rightOrigin = this.rightOrigin;
      const parentSub = this.parentSub;
      const info = (this.content.getRef() & BITS5) |
        (origin === null ? 0 : BIT8) | // origin is defined
        (rightOrigin === null ? 0 : BIT7) | // right origin is defined
        (parentSub === null ? 0 : BIT6); // parentSub is non-null
      encoder.writeInfo(info);
      if (origin !== null) {
        encoder.writeLeftID(origin);
      }
      if (rightOrigin !== null) {
        encoder.writeRightID(rightOrigin);
      }
      if (origin === null && rightOrigin === null) {
        const parent = /** @type {AbstractType<any>} */ (this.parent);
        if (parent._item !== undefined) {
          const parentItem = parent._item;
          if (parentItem === null) {
            // parent type on y._map
            // find the correct key
            const ykey = findRootTypeKey(parent);
            encoder.writeParentInfo(true); // write parentYKey
            encoder.writeString(ykey);
          } else {
            encoder.writeParentInfo(false); // write parent id
            encoder.writeLeftID(parentItem.id);
          }
        } else if (parent.constructor === String) { // this edge case was added by differential updates
          encoder.writeParentInfo(true); // write parentYKey
          encoder.writeString(parent);
        } else if (parent.constructor === ID) {
          encoder.writeParentInfo(false); // write parent id
          encoder.writeLeftID(parent);
        } else {
          unexpectedCase();
        }
        if (parentSub !== null) {
          encoder.writeString(parentSub);
        }
      }
      this.content.write(encoder, offset);
    }
  }

  /** eslint-env browser */

  const glo = /** @type {any} */ (typeof globalThis !== 'undefined'
    ? globalThis
    : typeof window !== 'undefined'
      ? window
      // @ts-ignore
      : typeof global !== 'undefined' ? global : {});

  const importIdentifier = '__ $YJS$ __';

  if (glo[importIdentifier] === true) {
    /**
     * Dear reader of this message. Please take this seriously.
     *
     * If you see this message, make sure that you only import one version of Yjs. In many cases,
     * your package manager installs two versions of Yjs that are used by different packages within your project.
     * Another reason for this message is that some parts of your project use the commonjs version of Yjs
     * and others use the EcmaScript version of Yjs.
     *
     * This often leads to issues that are hard to debug. We often need to perform constructor checks,
     * e.g. `struct instanceof GC`. If you imported different versions of Yjs, it is impossible for us to
     * do the constructor checks anymore - which might break the CRDT algorithm.
     *
     * https://github.com/yjs/yjs/issues/438
     */
    console.error('Yjs was already imported. This breaks constructor checks and will lead to issues! - https://github.com/yjs/yjs/issues/438');
  }
  glo[importIdentifier] = true;

  /**
   * @module awareness-protocol
   */


  const outdatedTimeout = 30000;

  /**
   * @typedef {Object} MetaClientState
   * @property {number} MetaClientState.clock
   * @property {number} MetaClientState.lastUpdated unix timestamp
   */

  /**
   * The Awareness class implements a simple shared state protocol that can be used for non-persistent data like awareness information
   * (cursor, username, status, ..). Each client can update its own local state and listen to state changes of
   * remote clients. Every client may set a state of a remote peer to `null` to mark the client as offline.
   *
   * Each client is identified by a unique client id (something we borrow from `doc.clientID`). A client can override
   * its own state by propagating a message with an increasing timestamp (`clock`). If such a message is received, it is
   * applied if the known state of that client is older than the new state (`clock < newClock`). If a client thinks that
   * a remote client is offline, it may propagate a message with
   * `{ clock: currentClientClock, state: null, client: remoteClient }`. If such a
   * message is received, and the known clock of that client equals the received clock, it will override the state with `null`.
   *
   * Before a client disconnects, it should propagate a `null` state with an updated clock.
   *
   * Awareness states must be updated every 30 seconds. Otherwise the Awareness instance will delete the client state.
   *
   * @extends {Observable<string>}
   */
  class Awareness extends Observable {
    /**
     * @param {Y.Doc} doc
     */
    constructor (doc) {
      super();
      this.doc = doc;
      /**
       * @type {number}
       */
      this.clientID = doc.clientID;
      /**
       * Maps from client id to client state
       * @type {Map<number, Object<string, any>>}
       */
      this.states = new Map();
      /**
       * @type {Map<number, MetaClientState>}
       */
      this.meta = new Map();
      this._checkInterval = /** @type {any} */ (setInterval(() => {
        const now = getUnixTime();
        if (this.getLocalState() !== null && (outdatedTimeout / 2 <= now - /** @type {{lastUpdated:number}} */ (this.meta.get(this.clientID)).lastUpdated)) {
          // renew local clock
          this.setLocalState(this.getLocalState());
        }
        /**
         * @type {Array<number>}
         */
        const remove = [];
        this.meta.forEach((meta, clientid) => {
          if (clientid !== this.clientID && outdatedTimeout <= now - meta.lastUpdated && this.states.has(clientid)) {
            remove.push(clientid);
          }
        });
        if (remove.length > 0) {
          removeAwarenessStates(this, remove, 'timeout');
        }
      }, floor(outdatedTimeout / 10)));
      doc.on('destroy', () => {
        this.destroy();
      });
      this.setLocalState({});
    }

    destroy () {
      this.emit('destroy', [this]);
      this.setLocalState(null);
      super.destroy();
      clearInterval(this._checkInterval);
    }

    /**
     * @return {Object<string,any>|null}
     */
    getLocalState () {
      return this.states.get(this.clientID) || null
    }

    /**
     * @param {Object<string,any>|null} state
     */
    setLocalState (state) {
      const clientID = this.clientID;
      const currLocalMeta = this.meta.get(clientID);
      const clock = currLocalMeta === undefined ? 0 : currLocalMeta.clock + 1;
      const prevState = this.states.get(clientID);
      if (state === null) {
        this.states.delete(clientID);
      } else {
        this.states.set(clientID, state);
      }
      this.meta.set(clientID, {
        clock,
        lastUpdated: getUnixTime()
      });
      const added = [];
      const updated = [];
      const filteredUpdated = [];
      const removed = [];
      if (state === null) {
        removed.push(clientID);
      } else if (prevState == null) {
        if (state != null) {
          added.push(clientID);
        }
      } else {
        updated.push(clientID);
        if (!equalityDeep(prevState, state)) {
          filteredUpdated.push(clientID);
        }
      }
      if (added.length > 0 || filteredUpdated.length > 0 || removed.length > 0) {
        this.emit('change', [{ added, updated: filteredUpdated, removed }, 'local']);
      }
      this.emit('update', [{ added, updated, removed }, 'local']);
    }

    /**
     * @param {string} field
     * @param {any} value
     */
    setLocalStateField (field, value) {
      const state = this.getLocalState();
      if (state !== null) {
        this.setLocalState({
          ...state,
          [field]: value
        });
      }
    }

    /**
     * @return {Map<number,Object<string,any>>}
     */
    getStates () {
      return this.states
    }
  }

  /**
   * Mark (remote) clients as inactive and remove them from the list of active peers.
   * This change will be propagated to remote clients.
   *
   * @param {Awareness} awareness
   * @param {Array<number>} clients
   * @param {any} origin
   */
  const removeAwarenessStates = (awareness, clients, origin) => {
    const removed = [];
    for (let i = 0; i < clients.length; i++) {
      const clientID = clients[i];
      if (awareness.states.has(clientID)) {
        awareness.states.delete(clientID);
        if (clientID === awareness.clientID) {
          const curMeta = /** @type {MetaClientState} */ (awareness.meta.get(clientID));
          awareness.meta.set(clientID, {
            clock: curMeta.clock + 1,
            lastUpdated: getUnixTime()
          });
        }
        removed.push(clientID);
      }
    }
    if (removed.length > 0) {
      awareness.emit('change', [{ added: [], updated: [], removed }, origin]);
      awareness.emit('update', [{ added: [], updated: [], removed }, origin]);
    }
  };

  /**
   * @param {Awareness} awareness
   * @param {Array<number>} clients
   * @return {Uint8Array}
   */
  const encodeAwarenessUpdate = (awareness, clients, states = awareness.states) => {
    const len = clients.length;
    const encoder = createEncoder();
    writeVarUint(encoder, len);
    for (let i = 0; i < len; i++) {
      const clientID = clients[i];
      const state = states.get(clientID) || null;
      const clock = /** @type {MetaClientState} */ (awareness.meta.get(clientID)).clock;
      writeVarUint(encoder, clientID);
      writeVarUint(encoder, clock);
      writeVarString(encoder, JSON.stringify(state));
    }
    return toUint8Array(encoder)
  };

  /**
   * @param {Awareness} awareness
   * @param {Uint8Array} update
   * @param {any} origin This will be added to the emitted change event
   */
  const applyAwarenessUpdate = (awareness, update, origin) => {
    const decoder = createDecoder(update);
    const timestamp = getUnixTime();
    const added = [];
    const updated = [];
    const filteredUpdated = [];
    const removed = [];
    const len = readVarUint(decoder);
    for (let i = 0; i < len; i++) {
      const clientID = readVarUint(decoder);
      let clock = readVarUint(decoder);
      const state = JSON.parse(readVarString(decoder));
      const clientMeta = awareness.meta.get(clientID);
      const prevState = awareness.states.get(clientID);
      const currClock = clientMeta === undefined ? 0 : clientMeta.clock;
      if (currClock < clock || (currClock === clock && state === null && awareness.states.has(clientID))) {
        if (state === null) {
          // never let a remote client remove this local state
          if (clientID === awareness.clientID && awareness.getLocalState() != null) {
            // remote client removed the local state. Do not remote state. Broadcast a message indicating
            // that this client still exists by increasing the clock
            clock++;
          } else {
            awareness.states.delete(clientID);
          }
        } else {
          awareness.states.set(clientID, state);
        }
        awareness.meta.set(clientID, {
          clock,
          lastUpdated: timestamp
        });
        if (clientMeta === undefined && state !== null) {
          added.push(clientID);
        } else if (clientMeta !== undefined && state === null) {
          removed.push(clientID);
        } else if (state !== null) {
          if (!equalityDeep(state, prevState)) {
            filteredUpdated.push(clientID);
          }
          updated.push(clientID);
        }
      }
    }
    if (added.length > 0 || filteredUpdated.length > 0 || removed.length > 0) {
      awareness.emit('change', [{
        added, updated: filteredUpdated, removed
      }, origin]);
    }
    if (added.length > 0 || updated.length > 0 || removed.length > 0) {
      awareness.emit('update', [{
        added, updated, removed
      }, origin]);
    }
  };

  /**
   * @param {t.TestCase} tc
   */
  const testAwareness = tc => {
    const doc1 = new Doc();
    doc1.clientID = 0;
    const doc2 = new Doc();
    doc2.clientID = 1;
    const aw1 = new Awareness(doc1);
    const aw2 = new Awareness(doc2);
    aw1.on('update', /** @param {any} p */ ({ added, updated, removed }) => {
      const enc = encodeAwarenessUpdate(aw1, added.concat(updated).concat(removed));
      applyAwarenessUpdate(aw2, enc, 'custom');
    });
    let lastChangeLocal = /** @type {any} */ (null);
    aw1.on('change', /** @param {any} change */ change => {
      lastChangeLocal = change;
    });
    let lastChange = /** @type {any} */ (null);
    aw2.on('change', /** @param {any} change */ change => {
      lastChange = change;
    });
    aw1.setLocalState({ x: 3 });
    compare(aw2.getStates().get(0), { x: 3 });
    assert(/** @type {any} */ (aw2.meta.get(0)).clock === 1);
    compare(lastChange.added, [0]);
    // When creating an Awareness instance, the the local client is already marked as available, so it is not updated.
    compare(lastChangeLocal, { added: [], updated: [0], removed: [] });

    // update state
    lastChange = null;
    lastChangeLocal = null;
    aw1.setLocalState({ x: 4 });
    compare(aw2.getStates().get(0), { x: 4 });
    compare(lastChangeLocal, { added: [], updated: [0], removed: [] });
    compare(lastChangeLocal, lastChange);

    lastChange = null;
    lastChangeLocal = null;
    aw1.setLocalState({ x: 4 });
    assert(lastChange === null);
    assert(/** @type {any} */ (aw2.meta.get(0)).clock === 3);
    compare(lastChangeLocal, lastChange);
    aw1.setLocalState(null);
    assert(lastChange.removed.length === 1);
    compare(aw1.getStates().get(0), undefined);
    compare(lastChangeLocal, lastChange);
  };

  var awareness = /*#__PURE__*/Object.freeze({
    __proto__: null,
    testAwareness: testAwareness
  });

  /* istanbul ignore if */
  if (isBrowser) {
    createVConsole(document.body);
  }

  runTests({
    awareness
  }).then(success => {
    /* istanbul ignore next */
    if (isNode) {
      process.exit(success ? 0 : 1);
    }
  });

})();
//# sourceMappingURL=test.js.map
