4nm/dist/EventEmitter/EventEmitter.js

TypeScript reimplementation of Telegram's official library for communicating with Telegram Web Apps.

/**
 * EventEmitter represents classic event emitter. It allows usage of known
 * events and expected types as long as unknown events.
 */
export class EventEmitter {
    /**
     * List of currently bound events listeners.
     * @private
     */
    listeners = {};
    /**
     * List of currently bound global event listeners.
     * @private
     */
    globalListeners = [];
    emit(event, ...args) {
        // Emit global listeners.
        this.globalListeners.forEach(l => l(event, ...args));
        // Emit event specific listeners.
        const listeners = this.listeners[event];
        if (listeners === undefined) {
            return;
        }
        listeners.forEach(l => l(...args));
    }
    /**
     * Emits unknown event. This function is recognized dangerous and should be
     * used carefully as long as this function ignores event typings.
     * @param event - event name.
     * @param args - list of event listener arguments.
     */
    emitUnsafe(event, ...args) {
        this.emit(event, ...args);
    }
    on(event, listener) {
        const listeners = this.listeners[event];
        if (listeners === undefined) {
            this.listeners[event] = [listener];
        }
        else {
            listeners.push(listener);
        }
    }
    off(event, listener) {
        const listeners = this.listeners[event];
        if (listeners === undefined) {
            return;
        }
        const idx = listeners.indexOf(listener);
        if (idx >= 0) {
            listeners.splice(idx, 1);
        }
    }
    /**
     * Subscribes to any events appearing.
     * @param listener - events listener.
     */
    subscribe(listener) {
        this.globalListeners.push(listener);
    }
    /**
     * Removes listener from global listeners.
     * @param listener - events listener.
     */
    unsubscribe(listener) {
        const idx = this.globalListeners.indexOf(listener);
        if (idx >= 0) {
            this.globalListeners.splice(idx, 1);
        }
    }
}