fix (service): add respect for fallback language for translateObject

libs/transloco/src/lib/tests/i18n-mocks/en.json

@@ -15,5 +15,9 @@
     "desc": "Desc english"
   },
   "key.is.like.path": "key is like path",
-  "empty": ""
+  "empty": "",
+  "fallback-object":{
+    "title": "Title english",
+    "desc": "Desc english"
+  }
 }

libs/transloco/src/lib/tests/service/translateObject.spec.ts

@@ -24,6 +24,23 @@ describe('translateObject', () => {
       });
     }));
 
+    it('should return a nested object from the fallback language', fakeAsync(() => {
+      service = createService({
+        fallbackLang: 'en',
+        missingHandler: {
+          useFallbackTranslation: true
+        }
+      })
+      loadLang(service, 'es');
+      loadLang(service, 'en');
+      service.setActiveLang('es');
+
+      expect(service.translateObject('fallback-object')).toEqual({
+        "title": "Title english",
+        "desc": "Desc english"
+      });
+    }));    
+
     it('should should support params', fakeAsync(() => {
       loadLang(service);
       expect(

libs/transloco/src/lib/transloco.service.ts

@@ -398,9 +398,10 @@ export class TranslocoService implements OnDestroy {
       key = scope ? `${scope}.${key}` : key;
 
       const value = unflatten(this.getObjectByKey(translation, key));
-      /* If an empty object was returned we want to try and translate the key as a string and not an object */
+      /* If an empty object was returned we want to try the same with the fallback language and afterwards translate 
+         the key as a string and not an object */
       return isEmpty(value)
-        ? this.translate(key, params!, lang)
+        ? this._handleMissingKeyForObject(key, value, params!, lang)
         : this.parser.transpile(value, params!, translation);
     }
 
@@ -624,6 +625,30 @@ export class TranslocoService implements OnDestroy {
     );
   }
 
+  /**
+   * @internal
+   */
+  _handleMissingKeyForObject(key: string, value: any, params: HashMap |  undefined, lang: string) {
+    if (this.config.missingHandler!.allowEmpty && value === '') {
+      return '';
+    }
+
+    if (!this.isResolvedMissingOnce && this.useFallbackTranslation()) {
+      // We need to set it to true to prevent a loop
+      this.isResolvedMissingOnce = true;
+      const fallbackValue = this.translateObject(
+        key,
+        params,
+        this.firstFallbackLang!
+      );
+      this.isResolvedMissingOnce = false;
+
+      return fallbackValue;
+    }
+
+    return this.translate(key, params!, lang);
+  }
+
   /**
    * @internal
    */