Use template literals instead of string concatenation (#3066)

We have used it inconsistently till now. Template literals are more
modern and easier to maintain in my opinion.

Because that's a large amount of changes, here's a way to reproduce it:
I added the rule `"prefer-template": "error"` to the `.eslintrc.json`
and did an autofix. Since this caused a new problem in line 409 of
`newsfeed.js`, I reversed it in that line and also removed the rule from
the eslint config file.

The rule is described here:
https://eslint.org/docs/latest/rules/prefer-template

Note: I've played around with some other linter rules as well, and some
seem to point to some specific, non-cosmetic, issues. But before I dive
even deeper and then introduce even bigger and hardly understandable
changes at once, I thought I'd start with this simple cosmetic rule.

js/app.js

@@ -18,7 +18,7 @@ const envsub = require("envsub");
 
 // Get version number.
 global.version = require(`${__dirname}/../package.json`).version;
-Log.log("Starting MagicMirror: v" + global.version);
+Log.log(`Starting MagicMirror: v${global.version}`);
 
 // global absolute root path
 global.root_path = path.resolve(`${__dirname}/../`);
@@ -64,7 +64,7 @@ function App() {
 		// For this check proposed to TestSuite
 		// https://forum.magicmirror.builders/topic/1456/test-suite-for-magicmirror/8
 		const configFilename = path.resolve(global.configuration_file || `${global.root_path}/config/config.js`);
-		let templateFile = configFilename + ".template";
+		let templateFile = `${configFilename}.template`;
 
 		// check if templateFile exists
 		try {
@@ -78,21 +78,21 @@ function App() {
 			// save current config.js
 			try {
 				if (fs.existsSync(configFilename)) {
-					fs.copyFileSync(configFilename, configFilename + "_" + Date.now());
+					fs.copyFileSync(configFilename, `${configFilename}_${Date.now()}`);
 				}
 			} catch (err) {
-				Log.warn("Could not copy " + configFilename + ": " + err.message);
+				Log.warn(`Could not copy ${configFilename}: ${err.message}`);
 			}
 
 			// check if config.env exists
 			const envFiles = [];
-			const configEnvFile = configFilename.substr(0, configFilename.lastIndexOf(".")) + ".env";
+			const configEnvFile = `${configFilename.substr(0, configFilename.lastIndexOf("."))}.env`;
 			try {
 				if (fs.existsSync(configEnvFile)) {
 					envFiles.push(configEnvFile);
 				}
 			} catch (err) {
-				Log.debug(configEnvFile + " does not exist. " + err.message);
+				Log.debug(`${configEnvFile} does not exist. ${err.message}`);
 			}
 
 			let options = {
@@ -110,7 +110,7 @@ function App() {
 			try {
 				await envsub({ templateFile, outputFile, options });
 			} catch (err) {
-				Log.error("Could not envsubst variables: " + err.message);
+				Log.error(`Could not envsubst variables: ${err.message}`);
 			}
 		}
 

js/loader.js

@@ -44,7 +44,7 @@ const Loader = (function () {
 		// Starting modules also hides any modules that have requested to be initially hidden
 		for (const thisModule of moduleObjects) {
 			if (thisModule.data.hiddenOnStartup) {
-				Log.info("Initially hiding " + thisModule.name);
+				Log.info(`Initially hiding ${thisModule.name}`);
 				thisModule.hide();
 			}
 		}
@@ -73,10 +73,10 @@ const Loader = (function () {
 
 			const elements = module.split("/");
 			const moduleName = elements[elements.length - 1];
-			let moduleFolder = config.paths.modules + "/" + module;
+			let moduleFolder = `${config.paths.modules}/${module}`;
 
 			if (defaultModules.indexOf(moduleName) !== -1) {
-				moduleFolder = config.paths.modules + "/default/" + module;
+				moduleFolder = `${config.paths.modules}/default/${module}`;
 			}
 
 			if (moduleData.disabled === true) {
@@ -85,16 +85,16 @@ const Loader = (function () {
 
 			moduleFiles.push({
 				index: index,
-				identifier: "module_" + index + "_" + module,
+				identifier: `module_${index}_${module}`,
 				name: moduleName,
-				path: moduleFolder + "/",
-				file: moduleName + ".js",
+				path: `${moduleFolder}/`,
+				file: `${moduleName}.js`,
 				position: moduleData.position,
 				hiddenOnStartup: moduleData.hiddenOnStartup,
 				header: moduleData.header,
 				configDeepMerge: typeof moduleData.configDeepMerge === "boolean" ? moduleData.configDeepMerge : false,
 				config: moduleData.config,
-				classes: typeof moduleData.classes !== "undefined" ? moduleData.classes + " " + module : module
+				classes: typeof moduleData.classes !== "undefined" ? `${moduleData.classes} ${module}` : module
 			});
 		});
 
@@ -136,17 +136,17 @@ const Loader = (function () {
 	 * @param {Module} mObj Modules instance.
 	 */
 	const bootstrapModule = async function (module, mObj) {
-		Log.info("Bootstrapping module: " + module.name);
+		Log.info(`Bootstrapping module: ${module.name}`);
 		mObj.setData(module);
 
 		await mObj.loadScripts();
-		Log.log("Scripts loaded for: " + module.name);
+		Log.log(`Scripts loaded for: ${module.name}`);
 
 		await mObj.loadStyles();
-		Log.log("Styles loaded for: " + module.name);
+		Log.log(`Styles loaded for: ${module.name}`);
 
 		await mObj.loadTranslations();
-		Log.log("Translations loaded for: " + module.name);
+		Log.log(`Translations loaded for: ${module.name}`);
 
 		moduleObjects.push(mObj);
 	};
@@ -164,7 +164,7 @@ const Loader = (function () {
 		switch (extension.toLowerCase()) {
 			case "js":
 				return new Promise((resolve) => {
-					Log.log("Load script: " + fileName);
+					Log.log(`Load script: ${fileName}`);
 					script = document.createElement("script");
 					script.type = "text/javascript";
 					script.src = fileName;
@@ -179,7 +179,7 @@ const Loader = (function () {
 				});
 			case "css":
 				return new Promise((resolve) => {
-					Log.log("Load stylesheet: " + fileName);
+					Log.log(`Load stylesheet: ${fileName}`);
 
 					stylesheet = document.createElement("link");
 					stylesheet.rel = "stylesheet";
@@ -236,7 +236,7 @@ const Loader = (function () {
 		 */
 		loadFileForModule: async function (fileName, module) {
 			if (loadedFiles.indexOf(fileName.toLowerCase()) !== -1) {
-				Log.log("File already loaded: " + fileName);
+				Log.log(`File already loaded: ${fileName}`);
 				return;
 			}
 
@@ -251,7 +251,7 @@ const Loader = (function () {
 				// This file is available in the vendor folder.
 				// Load it from this vendor folder.
 				loadedFiles.push(fileName.toLowerCase());
-				return loadFile(config.paths.vendor + "/" + vendor[fileName]);
+				return loadFile(`${config.paths.vendor}/${vendor[fileName]}`);
 			}
 
 			// File not loaded yet.

js/main.js

@@ -29,7 +29,7 @@ const MM = (function () {
 			dom.className = module.name;
 
 			if (typeof module.data.classes === "string") {
-				dom.className = "module " + dom.className + " " + module.data.classes;
+				dom.className = `module ${dom.className} ${module.data.classes}`;
 			}
 
 			dom.opacity = 0;
@@ -243,7 +243,7 @@ const MM = (function () {
 
 		const moduleWrapper = document.getElementById(module.identifier);
 		if (moduleWrapper !== null) {
-			moduleWrapper.style.transition = "opacity " + speed / 1000 + "s";
+			moduleWrapper.style.transition = `opacity ${speed / 1000}s`;
 			moduleWrapper.style.opacity = 0;
 			moduleWrapper.classList.add("hidden");
 
@@ -291,7 +291,7 @@ const MM = (function () {
 		// Check if there are no more lockstrings set, or the force option is set.
 		// Otherwise cancel show action.
 		if (module.lockStrings.length !== 0 && options.force !== true) {
-			Log.log("Will not show " + module.name + ". LockStrings active: " + module.lockStrings.join(","));
+			Log.log(`Will not show ${module.name}. LockStrings active: ${module.lockStrings.join(",")}`);
 			if (typeof options.onError === "function") {
 				options.onError(new Error("LOCK_STRING_ACTIVE"));
 			}
@@ -302,13 +302,13 @@ const MM = (function () {
 
 		// If forced show, clean current lockstrings.
 		if (module.lockStrings.length !== 0 && options.force === true) {
-			Log.log("Force show of module: " + module.name);
+			Log.log(`Force show of module: ${module.name}`);
 			module.lockStrings = [];
 		}
 
 		const moduleWrapper = document.getElementById(module.identifier);
 		if (moduleWrapper !== null) {
-			moduleWrapper.style.transition = "opacity " + speed / 1000 + "s";
+			moduleWrapper.style.transition = `opacity ${speed / 1000}s`;
 			// Restore the position. See hideModule() for more info.
 			moduleWrapper.style.position = "static";
 			moduleWrapper.classList.remove("hidden");

js/module.js

@@ -41,7 +41,7 @@ const Module = Class.extend({
 	 * Called when the module is started.
 	 */
 	start: async function () {
-		Log.info("Starting module: " + this.name);
+		Log.info(`Starting module: ${this.name}`);
 	},
 
 	/**
@@ -127,7 +127,7 @@ const Module = Class.extend({
 	 * @returns {string} The template string of filename.
 	 */
 	getTemplate: function () {
-		return '<div class="normal">' + this.name + '</div><div class="small dimmed">' + this.identifier + "</div>";
+		return `<div class="normal">${this.name}</div><div class="small dimmed">${this.identifier}</div>`;
 	},
 
 	/**
@@ -185,21 +185,21 @@ const Module = Class.extend({
 	 * @param {*} payload The payload of the notification.
 	 */
 	socketNotificationReceived: function (notification, payload) {
-		Log.log(this.name + " received a socket notification: " + notification + " - Payload: " + payload);
+		Log.log(`${this.name} received a socket notification: ${notification} - Payload: ${payload}`);
 	},
 
 	/**
 	 * Called when the module is hidden.
 	 */
 	suspend: function () {
-		Log.log(this.name + " is suspended.");
+		Log.log(`${this.name} is suspended.`);
 	},
 
 	/**
 	 * Called when the module is shown.
 	 */
 	resume: function () {
-		Log.log(this.name + " is resumed.");
+		Log.log(`${this.name} is resumed.`);
 	},
 
 	/*********************************************
@@ -255,7 +255,7 @@ const Module = Class.extend({
 	 * @returns {string} the file path
 	 */
 	file: function (file) {
-		return (this.data.path + "/" + file).replace("//", "/");
+		return `${this.data.path}/${file}`.replace("//", "/");
 	},
 
 	/**
@@ -491,15 +491,15 @@ Module.create = function (name) {
 
 Module.register = function (name, moduleDefinition) {
 	if (moduleDefinition.requiresVersion) {
-		Log.log("Check MagicMirror² version for module '" + name + "' - Minimum version:  " + moduleDefinition.requiresVersion + " - Current version: " + window.mmVersion);
+		Log.log(`Check MagicMirror² version for module '${name}' - Minimum version:  ${moduleDefinition.requiresVersion} - Current version: ${window.mmVersion}`);
 		if (cmpVersions(window.mmVersion, moduleDefinition.requiresVersion) >= 0) {
 			Log.log("Version is ok!");
 		} else {
-			Log.warn("Version is incorrect. Skip module: '" + name + "'");
+			Log.warn(`Version is incorrect. Skip module: '${name}'`);
 			return;
 		}
 	}
-	Log.log("Module registered: " + name);
+	Log.log(`Module registered: ${name}`);
 	Module.definitions[name] = moduleDefinition;
 };
 

js/server_functions.js

@@ -30,7 +30,7 @@ async function cors(req, res) {
 
 		const match = new RegExp(urlRegEx, "g").exec(req.url);
 		if (!match) {
-			url = "invalid url: " + req.url;
+			url = `invalid url: ${req.url}`;
 			Log.error(url);
 			res.send(url);
 		} else {
@@ -39,7 +39,7 @@ async function cors(req, res) {
 			const headersToSend = getHeadersToSend(req.url);
 			const expectedRecievedHeaders = geExpectedRecievedHeaders(req.url);
 
-			Log.log("cors url: " + url);
+			Log.log(`cors url: ${url}`);
 			const response = await fetch(url, { headers: headersToSend });
 
 			for (const header of expectedRecievedHeaders) {
@@ -62,7 +62,7 @@ async function cors(req, res) {
  * @returns {object} An object specifying name and value of the headers.
  */
 function getHeadersToSend(url) {
-	const headersToSend = { "User-Agent": "Mozilla/5.0 MagicMirror/" + global.version };
+	const headersToSend = { "User-Agent": `Mozilla/5.0 MagicMirror/${global.version}` };
 	const headersToSendMatch = new RegExp("sendheaders=(.+?)(&|$)", "g").exec(url);
 	if (headersToSendMatch) {
 		const headers = headersToSendMatch[1].split(",");

js/socketclient.js

@@ -18,8 +18,8 @@ const MMSocket = function (moduleName) {
 	if (typeof config !== "undefined" && typeof config.basePath !== "undefined") {
 		base = config.basePath;
 	}
-	this.socket = io("/" + this.moduleName, {
-		path: base + "socket.io"
+	this.socket = io(`/${this.moduleName}`, {
+		path: `${base}socket.io`
 	});
 
 	let notificationCallback = function () {};

js/translator.js

@@ -26,7 +26,7 @@ const Translator = (function () {
 						fileinfo = JSON.parse(xhr.responseText);
 					} catch (exception) {
 						// nothing here, but don't die
-						Log.error(" loading json file =" + file + " failed");
+						Log.error(` loading json file =${file} failed`);
 					}
 					resolve(fileinfo);
 				}
@@ -70,7 +70,7 @@ const Translator = (function () {
 					template = variables.fallback;
 				}
 				return template.replace(new RegExp("{([^}]+)}", "g"), function (_unused, varName) {
-					return varName in variables ? variables[varName] : "{" + varName + "}";
+					return varName in variables ? variables[varName] : `{${varName}}`;
 				});
 			}
 
@@ -123,7 +123,7 @@ const Translator = (function () {
 		 */
 		loadCoreTranslations: async function (lang) {
 			if (lang in translations) {
-				Log.log("Loading core translation file: " + translations[lang]);
+				Log.log(`Loading core translation file: ${translations[lang]}`);
 				this.coreTranslations = await loadJSON(translations[lang]);
 			} else {
 				Log.log("Configured language not found in core translations.");
@@ -139,7 +139,7 @@ const Translator = (function () {
 		loadCoreTranslationsFallback: async function () {
 			let first = Object.keys(translations)[0];
 			if (first) {
-				Log.log("Loading core translation fallback file: " + translations[first]);
+				Log.log(`Loading core translation fallback file: ${translations[first]}`);
 				this.coreTranslationsFallback = await loadJSON(translations[first]);
 			}
 		}