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1'use strict';2 3/**4 * Class representing an event.5 *6 * @private7 */8class Event {9  /**10   * Create a new `Event`.11   *12   * @param {String} type The name of the event13   * @param {Object} target A reference to the target to which the event was14   *     dispatched15   */16  constructor(type, target) {17    this.target = target;18    this.type = type;19  }20}21 22/**23 * Class representing a message event.24 *25 * @extends Event26 * @private27 */28class MessageEvent extends Event {29  /**30   * Create a new `MessageEvent`.31   *32   * @param {(String|Buffer|ArrayBuffer|Buffer[])} data The received data33   * @param {WebSocket} target A reference to the target to which the event was34   *     dispatched35   */36  constructor(data, target) {37    super('message', target);38 39    this.data = data;40  }41}42 43/**44 * Class representing a close event.45 *46 * @extends Event47 * @private48 */49class CloseEvent extends Event {50  /**51   * Create a new `CloseEvent`.52   *53   * @param {Number} code The status code explaining why the connection is being54   *     closed55   * @param {String} reason A human-readable string explaining why the56   *     connection is closing57   * @param {WebSocket} target A reference to the target to which the event was58   *     dispatched59   */60  constructor(code, reason, target) {61    super('close', target);62 63    this.wasClean = target._closeFrameReceived && target._closeFrameSent;64    this.reason = reason;65    this.code = code;66  }67}68 69/**70 * Class representing an open event.71 *72 * @extends Event73 * @private74 */75class OpenEvent extends Event {76  /**77   * Create a new `OpenEvent`.78   *79   * @param {WebSocket} target A reference to the target to which the event was80   *     dispatched81   */82  constructor(target) {83    super('open', target);84  }85}86 87/**88 * Class representing an error event.89 *90 * @extends Event91 * @private92 */93class ErrorEvent extends Event {94  /**95   * Create a new `ErrorEvent`.96   *97   * @param {Object} error The error that generated this event98   * @param {WebSocket} target A reference to the target to which the event was99   *     dispatched100   */101  constructor(error, target) {102    super('error', target);103 104    this.message = error.message;105    this.error = error;106  }107}108 109/**110 * This provides methods for emulating the `EventTarget` interface. It's not111 * meant to be used directly.112 *113 * @mixin114 */115const EventTarget = {116  /**117   * Register an event listener.118   *119   * @param {String} type A string representing the event type to listen for120   * @param {Function} listener The listener to add121   * @param {Object} [options] An options object specifies characteristics about122   *     the event listener123   * @param {Boolean} [options.once=false] A `Boolean`` indicating that the124   *     listener should be invoked at most once after being added. If `true`,125   *     the listener would be automatically removed when invoked.126   * @public127   */128  addEventListener(type, listener, options) {129    if (typeof listener !== 'function') return;130 131    function onMessage(data) {132      listener.call(this, new MessageEvent(data, this));133    }134 135    function onClose(code, message) {136      listener.call(this, new CloseEvent(code, message, this));137    }138 139    function onError(error) {140      listener.call(this, new ErrorEvent(error, this));141    }142 143    function onOpen() {144      listener.call(this, new OpenEvent(this));145    }146 147    const method = options && options.once ? 'once' : 'on';148 149    if (type === 'message') {150      onMessage._listener = listener;151      this[method](type, onMessage);152    } else if (type === 'close') {153      onClose._listener = listener;154      this[method](type, onClose);155    } else if (type === 'error') {156      onError._listener = listener;157      this[method](type, onError);158    } else if (type === 'open') {159      onOpen._listener = listener;160      this[method](type, onOpen);161    } else {162      this[method](type, listener);163    }164  },165 166  /**167   * Remove an event listener.168   *169   * @param {String} type A string representing the event type to remove170   * @param {Function} listener The listener to remove171   * @public172   */173  removeEventListener(type, listener) {174    const listeners = this.listeners(type);175 176    for (let i = 0; i < listeners.length; i++) {177      if (listeners[i] === listener || listeners[i]._listener === listener) {178        this.removeListener(type, listeners[i]);179      }180    }181  }182};183 184module.exports = EventTarget;185