event-emitters/dist.es5/EventEmitter.js

event emitters

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.EventEmitter = void 0;
var EventEmitterAsyncIterator_1 = require("./EventEmitterAsyncIterator");
/**
 * The same as node's EventEmitter but:
 * Only emits a single "event".
 * Throw an exception when a client registers the same listener more than once.
 * Throw an exception when a client tries to remove a listener that is not listening.
 */
var EventEmitter = /** @class */ (function () {
    function EventEmitter() {
        this.listeners = [];
    }
    EventEmitter.prototype.emit = function (newMessage) {
        this.listeners.forEach(function (listener) {
            listener(newMessage);
        });
    };
    EventEmitter.prototype.subscribe = function (listener) {
        if (this.listeners.includes(listener)) {
            throw new Error('You have already subscribed with this listener');
        }
        this.listeners.push(listener);
        return listener;
    };
    EventEmitter.prototype.unsubscribe = function (listener) {
        var index = this.listeners.indexOf(listener);
        if (index === -1) {
            throw new Error('Tried to remove listener that is not listening');
        }
        this.listeners.splice(index, 1);
    };
    EventEmitter.prototype.hasListeners = function () {
        return this.listeners.length !== 0;
    };
    EventEmitter.prototype[Symbol.asyncIterator] = function () {
        return this.asyncIterator();
    };
    EventEmitter.prototype.asyncIterator = function () {
        return new EventEmitterAsyncIterator_1.EventEmitterAsyncIterator(this);
    };
    return EventEmitter;
}());
exports.EventEmitter = EventEmitter;
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