feat: load timeago strings client-side

9adaccd036 introduced the ability to
configure an assetBaseUrl, but the timeago strings were still
calling a hardcoded value as it was handled server-side. There's
no need for the strings to be loaded until timeago is initialised.

public/src/app.js

@@ -252,7 +252,11 @@ app.cacheBuster = null;
 	app.processPage = function () {
 		highlightNavigationLink();
 
-		$('.timeago').timeago();
+		app.initTimeago().then(function () {
+			$('.timeago').timeago();
+		}, function () {
+			console.warn('[timeago] Unable to retrieve ' + config.userLang + ' strings, falling back to English');
+		});
 
 		utils.makeNumbersHumanReadable($('.human-readable-number'));
 
@@ -268,6 +272,21 @@ app.cacheBuster = null;
 		}
 	};
 
+	app.initTimeago = function () {
+		// Loads strings based on user language, if not already loaded
+		return new Promise(function (resolve, reject) {
+			if (app.flags._timeago) {
+				return resolve();
+			}
+
+			var pathToLocaleFile = '/vendor/jquery/timeago/locales/jquery.timeago.' + utils.userLangToTimeagoCode(config.userLang) + '.js';
+			$.getScript(config.assetBaseUrl + pathToLocaleFile).done(function () {
+				app.flags._timeago = true;
+				resolve();
+			}).fail(reject);
+		});
+	};
+
 	app.showMessages = function () {
 		var messages = {
 			login: {

src/middleware/header.js

@@ -15,7 +15,6 @@ var plugins = require('../plugins');
 var navigation = require('../navigation');
 var translator = require('../translator');
 var privileges = require('../privileges');
-var languages = require('../languages');
 var utils = require('../utils');
 var helpers = require('./helpers');
 
@@ -188,25 +187,8 @@ module.exports = function (middleware) {
 			templateValues: templateValues,
 		});
 
-		const results = await utils.promiseParallel({
-			scripts: plugins.fireHook('filter:scripts.get', []),
-			timeagoLocale: (async () => {
-				const languageCodes = await languages.listCodes();
-				const userLang = res.locals.config.userLang;
-				const timeagoCode = utils.userLangToTimeagoCode(userLang);
-
-				if (languageCodes.includes(userLang) && languages.timeagoCodes.includes(timeagoCode)) {
-					const pathToLocaleFile = '/vendor/jquery/timeago/locales/jquery.timeago.' + timeagoCode + '.js';
-					return nconf.get('relative_path') + '/assets' + pathToLocaleFile;
-				}
-				return false;
-			})(),
-		});
-
-		if (results.timeagoLocale) {
-			results.scripts.push(results.timeagoLocale);
-		}
-		data.templateValues.scripts = results.scripts.map(function (script) {
+		const scripts = await plugins.fireHook('filter:scripts.get', []);
+		data.templateValues.scripts = scripts.map(function (script) {
 			return { src: script };
 		});