60 lines
1.0 KiB
TypeScript
60 lines
1.0 KiB
TypeScript
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import { IDisposable } from "@coder/disposable";
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export interface Event<T> {
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(listener: (e: T) => void): IDisposable;
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}
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/**
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* Emitter typecasts for a single event type
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*/
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export class Emitter<T> {
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private listeners: Array<(e: T) => void> | undefined;
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public constructor() {
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this.listeners = [];
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}
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public get event(): Event<T> {
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return (cb: (e: T) => void): IDisposable => {
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if (this.listeners) {
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this.listeners.push(cb);
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}
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return {
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dispose: (): void => {
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if (this.listeners) {
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const i = this.listeners.indexOf(cb);
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if (i !== -1) {
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this.listeners.splice(i, 1);
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}
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}
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},
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};
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};
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}
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/**
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* Emit a value
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*/
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public emit(value: T): void {
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if (this.listeners) {
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this.listeners.forEach((t) => t(value));
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}
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}
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/**
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* Disposes the event emitter
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*/
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public dispose(): void {
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this.listeners = undefined;
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}
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/**
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* Whether the event has listeners.
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*/
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public get hasListeners(): boolean {
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return !!this.listeners && this.listeners.length > 0;
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}
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}
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