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