Add public API for loading js files asynchronously

Signed-off-by: Julius Härtl <jus@bitgrid.net>

core/js/js.js

@@ -39,7 +39,7 @@ function escapeHTML(s) {
 }
 
 /** @namespace OCP */
-var OCP = {},
+var OCP = Object.assign({}, window.OCP),
 	/**
 	 * @namespace OC
 	 */
@@ -367,6 +367,7 @@ var OCP = {},
 	 * @param {string} app the app id to which the script belongs
 	 * @param {string} script the filename of the script
 	 * @param ready event handler to be called when the script is loaded
+	 * @deprecated 16.0.0 Use OCP.Loader.loadScript
 	 */
 	addScript:function(app,script,ready){
 		var deferred, path=OC.filePath(app,'js',script+'.js');
@@ -387,6 +388,7 @@ var OCP = {},
 	 * Loads a CSS file
 	 * @param {string} app the app id to which the css style belongs
 	 * @param {string} style the filename of the css file
+	 * @deprecated 16.0.0 Use OCP.Loader.loadStylesheet
 	 */
 	addStyle:function(app,style){
 		var path=OC.filePath(app,'css',style+'.css');

core/src/OCP/index.js

@@ -0,0 +1,11 @@
+/**
+ *
+ */
+import loader from './loader'
+
+/** @namespace OCP */
+const OCP = {
+	Loader: loader,
+};
+
+window['OCP'] = Object.assign({}, window.OCP, OCP)

core/src/OCP/loader.js

@@ -0,0 +1,80 @@
+/*
+ * @copyright Copyright (c) 2018 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+let loadedScripts = {};
+let loadedStylesheets = {};
+/**
+ * @namespace OCP
+ * @class Loader
+ */
+export default {
+
+
+	/**
+	 * Load a script asynchronously
+	 *
+	 * @param {string} app
+	 * @param {string} file
+	 * @returns {Promise}
+	 */
+	loadScript: function(app, file) {
+		const key = app + file;
+		if (loadedScripts.hasOwnProperty(key)) {
+			return Promise.resolve();
+		}
+		loadedScripts[key] = true;
+		return new Promise(function (resolve, reject) {
+			var scriptPath = OC.filePath(app, 'js', file);
+			var script = document.createElement('script');
+			script.src = scriptPath;
+			script.setAttribute('nonce', btoa(OC.requestToken));
+			script.onload = () => resolve();
+			script.onerror = () => reject(`Failed to load script from ${scriptPath}`);
+			document.head.appendChild(script);
+		});
+	},
+
+	/**
+	 * Load a stylesheet file asynchronously
+	 *
+	 * @param {string} app
+	 * @param {string} file
+	 * @returns {Promise}
+	 */
+	loadStylesheet: function(app, file) {
+		const key = app + file;
+		if (loadedStylesheets.hasOwnProperty(key)) {
+			return Promise.resolve();
+		}
+		loadedStylesheets[key] = true;
+		return new Promise(function (resolve, reject) {
+			var stylePath = OC.filePath(app, 'css', file);
+			var link = document.createElement('link');
+			link.href = stylePath;
+			link.type = 'text/css';
+			link.rel = 'stylesheet';
+			link.onload = () => resolve();
+			link.onerror = () => reject(`Failed to load stylesheet from ${stylePath}`);
+			document.head.appendChild(link);
+		});
+	},
+}

core/src/main.js

@@ -22,3 +22,5 @@
 import '@babel/polyfill'
 
 import './globals'
+
+import './OCP/index'