| 1 | /* |
| 2 | * noVNC: HTML5 VNC client |
| 3 | * Copyright (C) 2019 The noVNC Authors |
| 4 | * Licensed under MPL 2.0 (see LICENSE.txt) |
| 5 | * |
| 6 | * See README.md for usage and integration instructions. |
| 7 | */ |
| 8 | |
| 9 | export default class EventTargetMixin { |
| 10 | constructor() { |
| 11 | this._listeners = new Map(); |
| 12 | } |
| 13 | |
| 14 | addEventListener(type, callback) { |
| 15 | if (!this._listeners.has(type)) { |
| 16 | this._listeners.set(type, new Set()); |
| 17 | } |
| 18 | this._listeners.get(type).add(callback); |
| 19 | } |
| 20 | |
| 21 | removeEventListener(type, callback) { |
| 22 | if (this._listeners.has(type)) { |
| 23 | this._listeners.get(type).delete(callback); |
| 24 | } |
| 25 | } |
| 26 | |
| 27 | dispatchEvent(event) { |
| 28 | if (!this._listeners.has(event.type)) { |
| 29 | return true; |
| 30 | } |
| 31 | this._listeners.get(event.type) |
| 32 | .forEach(callback => callback.call(this, event)); |
| 33 | return !event.defaultPrevented; |
| 34 | } |
| 35 | } |