code-server-2/packages/events/src/events.ts

60 lines
1.0 KiB
TypeScript

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