Fix localization of unknown strings on client

src/mibew/js/source/default/localization.js

@@ -37,15 +37,14 @@
      * @returns {String} Localized string.
      */
     Mibew.Localization.trans = function(str) {
-        if (! localStrings.hasOwnProperty(str)) {
-            return false;
-        }
-
         // Replace "{n}" style placeholders with specified arguments. The first
         // argument is skipped because it is the localized string.
         var placeholders = Array.prototype.slice.call(arguments, 1);
 
-        return localStrings[str].replace(/\{([0-9]+)\}/g, function(match, index) {
+        // If there is no localized string use passed in one.
+        var localized = localStrings.hasOwnProperty(str) ? localStrings[str] : str;
+
+        return localized.replace(/\{([0-9]+)\}/g, function(match, index) {
             return placeholders[parseInt(index)] || '';
         });
     }

src/tests/client_side/qunit/test_cases/localization_tests.js

@@ -20,3 +20,17 @@ test('Basic things', function() {
         'Test placeholders'
     );
 });
+
+test('Unknown string', function() {
+    equal(
+        Mibew.Localization.trans('An unknown string'),
+        'An unknown string',
+        'Test simple string'
+    );
+
+    equal(
+        Mibew.Localization.trans('An unknown string with a placeholder: {0}', 'test!'),
+        'An unknown string with a placeholder: test!',
+        'Test placeholders'
+    );
+})