birch-event-emitter/dist/index.js

Simple Event Emitter

export class Disposable {
    constructor(disposer) {
        this.disposer = disposer;
    }
    dispose(...args) {
        this.disposer.apply(this.disposer, args);
    }
}
export class DisposablesComposite {
    constructor() {
        this.disposables = new Set();
    }
    add(disposable) {
        this.disposables.add(disposable);
        return disposable;
    }
    dispose(...args) {
        this.disposables.forEach(disposable => {
            disposable.dispose.apply(disposable, args);
        });
        this.disposables = new Set();
    }
}
export class EventEmitter {
    constructor() {
        this.listeners = new Map();
        this.onceListeners = new Map();
    }
    emit(event, ...args) {
        const callbacks = this.listeners.get(event);
        if (callbacks) {
            callbacks.forEach(cb => cb(...args));
        }
        const onceCallbacks = this.onceListeners.get(event);
        if (onceCallbacks) {
            onceCallbacks.forEach(cb => cb(...args));
            this.onceListeners.delete(event);
        }
    }
    on(event, cb) {
        if (!this.listeners.has(event)) {
            this.listeners.set(event, new Set());
        }
        const existing = this.listeners.get(event);
        existing.add(cb);
        return new Disposable(() => {
            existing.delete(cb);
        });
    }
    once(event, cb) {
        if (!this.onceListeners.has(event)) {
            this.onceListeners.set(event, new Set());
        }
        const existing = this.onceListeners.get(event);
        existing.add(cb);
        return new Disposable(() => {
            existing.delete(cb);
        });
    }
    emitWithReturn(event, ...args) {
        const callbacks = Array.from(this.listeners.get(event) || []);
        return callbacks.map(cb => cb(...args));
    }
    clear(event) {
        if (event) {
            this.listeners.delete(event);
            this.onceListeners.delete(event);
        }
        else {
            this.listeners.clear();
            this.onceListeners.clear();
        }
    }
}