Fix translation fallbacks

renderer/src/modules/localemanager.js

@@ -32,7 +32,7 @@ export default new class LocaleManager {
             newStrings = Locales[this.defaultLocale];
         }
         this.locale = newLocale;
-        Utilities.extend(this.strings, newStrings);
+        Utilities.extendTruthy(this.strings, newStrings);
         Events.emit("strings-updated");
     }
 };

renderer/src/modules/utilities.js

@@ -192,6 +192,35 @@ export default class Utilities {
         return extendee;
     }
 
+    /**
+     * Deep extends an object with a set of other objects. Objects later in the list
+     * of `extenders` have priority, that is to say if one sets a key to be a primitive,
+     * it will be overwritten with the next one with the same key. If it is an object,
+     * and the keys match, the object is extended. This happens recursively.
+     * @param {object} extendee - Object to be extended
+     * @param {...object} extenders - Objects to extend with
+     * @returns {object} - A reference to `extendee`
+     */
+    static extendTruthy(extendee, ...extenders) {
+        for (let i = 0; i < extenders.length; i++) {
+            for (const key in extenders[i]) {
+                if (extenders[i].hasOwnProperty(key)) {
+                    if (typeof extendee[key] === "object" && typeof extenders[i][key] === "object") {
+                        this.extendTruthy(extendee[key], extenders[i][key]);
+                    }
+                    else if (typeof extenders[i][key] === "object") {
+                        extendee[key] = {};
+                        this.extendTruthy(extendee[key], extenders[i][key]);
+                    }
+                    else if (extenders[i][key]) {
+                        extendee[key] = extenders[i][key];
+                    }
+                }
+            }
+        }
+        return extendee;
+    }
+
     /**
      * Format strings with placeholders (`{{placeholder}}`) into full strings.
      * Quick example: `PluginUtilities.formatString("Hello, {{user}}", {user: "Zerebos"})`