Convert translator callbacks to async/await (#3048)

Co-authored-by: veeck <michael@veeck.de>

js/loader.js

@@ -160,7 +160,7 @@ const Loader = (function () {
 			Log.log("Scripts loaded for: " + module.name);
 			mObj.loadStyles(function () {
 				Log.log("Styles loaded for: " + module.name);
-				mObj.loadTranslations(function () {
+				mObj.loadTranslations().then(() => {
 					Log.log("Translations loaded for: " + module.name);
 					moduleObjects.push(mObj);
 					callback();

js/main.js

@@ -485,8 +485,7 @@ const MM = (function () {
 
 			Log.setLogLevel(config.logLevel);
 
-			Translator.loadCoreTranslations(config.language);
-			Loader.loadModules();
+			Translator.loadCoreTranslations(config.language).then(() => Loader.loadModules());
 		},
 
 		/**

js/module.js

@@ -302,10 +302,8 @@ const Module = Class.extend({
 
 	/**
 	 * Load all translations.
-	 *
-	 * @param {Function} callback Function called when done.
 	 */
-	loadTranslations(callback) {
+	async loadTranslations() {
 		const translations = this.getTranslations() || {};
 		const language = config.language.toLowerCase();
 
@@ -313,7 +311,6 @@ const Module = Class.extend({
 		const fallbackLanguage = languages[0];
 
 		if (languages.length === 0) {
-			callback();
 			return;
 		}
 
@@ -321,17 +318,14 @@ const Module = Class.extend({
 		const translationsFallbackFile = translations[fallbackLanguage];
 
 		if (!translationFile) {
-			Translator.load(this, translationsFallbackFile, true, callback);
-			return;
+			return Translator.load(this, translationsFallbackFile, true);
 		}
 
-		Translator.load(this, translationFile, false, () => {
-			if (translationFile !== translationsFallbackFile) {
-				Translator.load(this, translationsFallbackFile, true, callback);
-			} else {
-				callback();
-			}
-		});
+		await Translator.load(this, translationFile, false);
+
+		if (translationFile !== translationsFallbackFile) {
+			return Translator.load(this, translationsFallbackFile, true);
+		}
 	},
 
 	/**

js/translator.js

@@ -11,26 +11,28 @@ const Translator = (function () {
 	 * Load a JSON file via XHR.
 	 *
 	 * @param {string} file Path of the file we want to load.
-	 * @param {Function} callback Function called when done.
+	 * @returns {Promise<object>} the translations in the specified file
 	 */
-	function loadJSON(file, callback) {
+	async function loadJSON(file) {
 		const xhr = new XMLHttpRequest();
-		xhr.overrideMimeType("application/json");
-		xhr.open("GET", file, true);
-		xhr.onreadystatechange = function () {
-			if (xhr.readyState === 4 && xhr.status === 200) {
-				// needs error handler try/catch at least
-				let fileinfo = null;
-				try {
-					fileinfo = JSON.parse(xhr.responseText);
-				} catch (exception) {
-					// nothing here, but don't die
-					Log.error(" loading json file =" + file + " failed");
+		return new Promise(function (resolve, reject) {
+			xhr.overrideMimeType("application/json");
+			xhr.open("GET", file, true);
+			xhr.onreadystatechange = function () {
+				if (xhr.readyState === 4 && xhr.status === 200) {
+					// needs error handler try/catch at least
+					let fileinfo = null;
+					try {
+						fileinfo = JSON.parse(xhr.responseText);
+					} catch (exception) {
+						// nothing here, but don't die
+						Log.error(" loading json file =" + file + " failed");
+					}
+					resolve(fileinfo);
 				}
-				callback(fileinfo);
-			}
-		};
-		xhr.send(null);
+			};
+			xhr.send(null);
+		});
 	}
 
 	return {
@@ -48,7 +50,7 @@ const Translator = (function () {
 		 * @returns {string} the translated key
 		 */
 		translate: function (module, key, variables) {
-			variables = variables || {}; //Empty object by default
+			variables = variables || {}; // Empty object by default
 
 			/**
 			 * Combines template and variables like:
@@ -101,21 +103,17 @@ const Translator = (function () {
 		 * @param {Module} module The module to load the translation file for.
 		 * @param {string} file Path of the file we want to load.
 		 * @param {boolean} isFallback Flag to indicate fallback translations.
-		 * @param {Function} callback Function called when done.
 		 */
-		load(module, file, isFallback, callback) {
+		async load(module, file, isFallback) {
 			Log.log(`${module.name} - Load translation${isFallback ? " fallback" : ""}: ${file}`);
 
 			if (this.translationsFallback[module.name]) {
-				callback();
 				return;
 			}
 
-			loadJSON(module.file(file), (json) => {
-				const property = isFallback ? "translationsFallback" : "translations";
-				this[property][module.name] = json;
-				callback();
-			});
+			const json = await loadJSON(module.file(file));
+			const property = isFallback ? "translationsFallback" : "translations";
+			this[property][module.name] = json;
 		},
 
 		/**
@@ -123,30 +121,26 @@ const Translator = (function () {
 		 *
 		 * @param {string} lang The language identifier of the core language.
 		 */
-		loadCoreTranslations: function (lang) {
+		loadCoreTranslations: async function (lang) {
 			if (lang in translations) {
 				Log.log("Loading core translation file: " + translations[lang]);
-				loadJSON(translations[lang], (translations) => {
-					this.coreTranslations = translations;
-				});
+				this.coreTranslations = await loadJSON(translations[lang]);
 			} else {
 				Log.log("Configured language not found in core translations.");
 			}
 
-			this.loadCoreTranslationsFallback();
+			await this.loadCoreTranslationsFallback();
 		},
 
 		/**
-		 * Load the core translations fallback.
+		 * Load the core translations' fallback.
 		 * The first language defined in translations.js will be used.
 		 */
-		loadCoreTranslationsFallback: function () {
+		loadCoreTranslationsFallback: async function () {
 			let first = Object.keys(translations)[0];
 			if (first) {
 				Log.log("Loading core translation fallback file: " + translations[first]);
-				loadJSON(translations[first], (translations) => {
-					this.coreTranslationsFallback = translations;
-				});
+				this.coreTranslationsFallback = await loadJSON(translations[first]);
 			}
 		}
 	};