Source: util/Observer.es.js

/**
 * Copyright (c) 2000-present Liferay, Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 * details.
 */

export default class Observer {
	constructor() {
		this.handlers = [];
	}

	subscribe(fn) {
		this.handlers.push(fn);
	}

	unsubscribe(fn) {
		this.handlers = this.handlers.filter((handler) => handler !== fn);
	}

	dispatch(value) {
		this.handlers.forEach((handler) => handler(value));
	}
}