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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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/**
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* A simple Javascript PubSub implementation.
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*
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* @module core/pubsub
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* @copyright 2018 Ryan Wyllie <ryan@moodle.com>
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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import Pending from 'core/pending';
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const events = {};
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/**
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* Subscribe to an event.
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*
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* @param {string} eventName The name of the event to subscribe to.
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* @param {function} callback The callback function to run when eventName occurs.
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*/
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export const subscribe = function(eventName, callback) {
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events[eventName] = events[eventName] || [];
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events[eventName].push(callback);
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};
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/**
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* Unsubscribe from an event.
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*
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* @param {string} eventName The name of the event to unsubscribe from.
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* @param {function} callback The callback to unsubscribe.
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*/
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export const unsubscribe = function(eventName, callback) {
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if (events[eventName]) {
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for (var i = 0; i < events[eventName].length; i++) {
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if (events[eventName][i] === callback) {
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events[eventName].splice(i, 1);
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break;
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}
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}
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}
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};
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/**
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* Publish an event to all subscribers.
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*
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* @param {string} eventName The name of the event to publish.
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* @param {any} data The data to provide to the subscribed callbacks.
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*/
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export const publish = function(eventName, data) {
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const pendingPromise = new Pending("Publishing " + eventName);
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if (events[eventName]) {
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events[eventName].forEach(function(callback) {
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callback(data);
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});
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}
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pendingPromise.resolve();
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};
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