--- /dev/null
+'use strict';
+
+/**
+ * Class representing an event.
+ *
+ * @private
+ */
+class Event {
+ /**
+ * Create a new `Event`.
+ *
+ * @param {String} type The name of the event
+ * @param {Object} target A reference to the target to which the event was dispatched
+ */
+ constructor (type, target) {
+ this.target = target;
+ this.type = type;
+ }
+}
+
+/**
+ * Class representing a message event.
+ *
+ * @extends Event
+ * @private
+ */
+class MessageEvent extends Event {
+ /**
+ * Create a new `MessageEvent`.
+ *
+ * @param {(String|Buffer|ArrayBuffer|Buffer[])} data The received data
+ * @param {WebSocket} target A reference to the target to which the event was dispatched
+ */
+ constructor (data, target) {
+ super('message', target);
+
+ this.data = data;
+ }
+}
+
+/**
+ * Class representing a close event.
+ *
+ * @extends Event
+ * @private
+ */
+class CloseEvent extends Event {
+ /**
+ * Create a new `CloseEvent`.
+ *
+ * @param {Number} code The status code explaining why the connection is being closed
+ * @param {String} reason A human-readable string explaining why the connection is closing
+ * @param {WebSocket} target A reference to the target to which the event was dispatched
+ */
+ constructor (code, reason, target) {
+ super('close', target);
+
+ this.wasClean = target._closeFrameReceived && target._closeFrameSent;
+ this.reason = reason;
+ this.code = code;
+ }
+}
+
+/**
+ * Class representing an open event.
+ *
+ * @extends Event
+ * @private
+ */
+class OpenEvent extends Event {
+ /**
+ * Create a new `OpenEvent`.
+ *
+ * @param {WebSocket} target A reference to the target to which the event was dispatched
+ */
+ constructor (target) {
+ super('open', target);
+ }
+}
+
+/**
+ * Class representing an error event.
+ *
+ * @extends Event
+ * @private
+ */
+class ErrorEvent extends Event {
+ /**
+ * Create a new `ErrorEvent`.
+ *
+ * @param {Object} error The error that generated this event
+ * @param {WebSocket} target A reference to the target to which the event was dispatched
+ */
+ constructor (error, target) {
+ super('error', target);
+
+ this.message = error.message;
+ this.error = error;
+ }
+}
+
+/**
+ * This provides methods for emulating the `EventTarget` interface. It's not
+ * meant to be used directly.
+ *
+ * @mixin
+ */
+const EventTarget = {
+ /**
+ * Register an event listener.
+ *
+ * @param {String} method A string representing the event type to listen for
+ * @param {Function} listener The listener to add
+ * @public
+ */
+ addEventListener (method, listener) {
+ if (typeof listener !== 'function') return;
+
+ function onMessage (data) {
+ listener.call(this, new MessageEvent(data, this));
+ }
+
+ function onClose (code, message) {
+ listener.call(this, new CloseEvent(code, message, this));
+ }
+
+ function onError (error) {
+ listener.call(this, new ErrorEvent(error, this));
+ }
+
+ function onOpen () {
+ listener.call(this, new OpenEvent(this));
+ }
+
+ if (method === 'message') {
+ onMessage._listener = listener;
+ this.on(method, onMessage);
+ } else if (method === 'close') {
+ onClose._listener = listener;
+ this.on(method, onClose);
+ } else if (method === 'error') {
+ onError._listener = listener;
+ this.on(method, onError);
+ } else if (method === 'open') {
+ onOpen._listener = listener;
+ this.on(method, onOpen);
+ } else {
+ this.on(method, listener);
+ }
+ },
+
+ /**
+ * Remove an event listener.
+ *
+ * @param {String} method A string representing the event type to remove
+ * @param {Function} listener The listener to remove
+ * @public
+ */
+ removeEventListener (method, listener) {
+ const listeners = this.listeners(method);
+
+ for (var i = 0; i < listeners.length; i++) {
+ if (listeners[i] === listener || listeners[i]._listener === listener) {
+ this.removeListener(method, listeners[i]);
+ }
+ }
+ }
+};
+
+module.exports = EventTarget;