89 lines
2.5 KiB
TypeScript
89 lines
2.5 KiB
TypeScript
// Copyright 2020-2022 Signal Messenger, LLC
|
|
// SPDX-License-Identifier: AGPL-3.0-only
|
|
|
|
/* eslint-disable @typescript-eslint/explicit-module-boundary-types */
|
|
/* eslint-disable @typescript-eslint/no-explicit-any */
|
|
/* eslint-disable guard-for-in */
|
|
/* eslint-disable no-restricted-syntax */
|
|
|
|
/*
|
|
* Implements EventTarget
|
|
* https://developer.mozilla.org/en-US/docs/Web/API/EventTarget
|
|
*/
|
|
|
|
export type EventHandler = (event: any) => unknown;
|
|
|
|
export default class EventTarget {
|
|
listeners?: { [type: string]: Array<EventHandler> };
|
|
|
|
dispatchEvent(ev: Event): Array<unknown> {
|
|
if (!(ev instanceof Event)) {
|
|
throw new Error('Expects an event');
|
|
}
|
|
if (this.listeners == null || typeof this.listeners !== 'object') {
|
|
this.listeners = {};
|
|
}
|
|
const listeners = this.listeners[ev.type];
|
|
const results = [];
|
|
if (typeof listeners === 'object') {
|
|
const max = listeners.length;
|
|
for (let i = 0; i < max; i += 1) {
|
|
const listener = listeners[i];
|
|
if (typeof listener === 'function') {
|
|
results.push(listener.call(null, ev));
|
|
}
|
|
}
|
|
}
|
|
return results;
|
|
}
|
|
|
|
addEventListener(eventName: string, callback: EventHandler): void {
|
|
if (typeof eventName !== 'string') {
|
|
throw new Error('First argument expects a string');
|
|
}
|
|
if (typeof callback !== 'function') {
|
|
throw new Error('Second argument expects a function');
|
|
}
|
|
if (this.listeners == null || typeof this.listeners !== 'object') {
|
|
this.listeners = {};
|
|
}
|
|
let listeners = this.listeners[eventName];
|
|
if (typeof listeners !== 'object') {
|
|
listeners = [];
|
|
}
|
|
listeners.push(callback);
|
|
this.listeners[eventName] = listeners;
|
|
}
|
|
|
|
removeEventListener(eventName: string, callback: EventHandler): void {
|
|
if (typeof eventName !== 'string') {
|
|
throw new Error('First argument expects a string');
|
|
}
|
|
if (typeof callback !== 'function') {
|
|
throw new Error('Second argument expects a function');
|
|
}
|
|
if (this.listeners == null || typeof this.listeners !== 'object') {
|
|
this.listeners = {};
|
|
}
|
|
const listeners = this.listeners[eventName];
|
|
if (typeof listeners === 'object') {
|
|
for (let i = 0; i < listeners.length; i += 1) {
|
|
if (listeners[i] === callback) {
|
|
listeners.splice(i, 1);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
this.listeners[eventName] = listeners;
|
|
}
|
|
|
|
extend(source: any): any {
|
|
const target = this as any;
|
|
|
|
for (const prop in source) {
|
|
target[prop] = source[prop];
|
|
}
|
|
return target;
|
|
}
|
|
}
|