feat(transloco): 🎸 allow to omit available languages

docs/docs/getting-started/config-options.mdx

@@ -60,6 +60,8 @@ translocoConfig({
   availableLangs: ['en', 'es']
 })
 ```
+When the active language is not included in the `availableLangs`, the translations of this language will not be returned.
+You can omit this option or set it to `null`, in this case the translations will be returned for any language, if available.
 
 ### `missingHandler.allowEmpty`
 Whether to allow empty values: (defaults to `false`)

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

@@ -79,4 +79,16 @@ describe('translate', () => {
       'Admin Lazy spanish'
     );
   }));
+
+  it('should return the translation when availableLangs is skipped', fakeAsync(() => {
+    service.setAvailableLangs(undefined);
+    loadLang(service);
+    expect(service.translate('home')).toEqual(mockLangs['en'].home);
+  }));
+
+  it('should return the translation when availableLangs is set to null', fakeAsync(() => {
+    service.setAvailableLangs(null);
+    loadLang(service);
+    expect(service.translate('home')).toEqual(mockLangs['en'].home);
+  }));
 });

libs/transloco/src/lib/transloco.config.ts

@@ -8,7 +8,7 @@
   prodMode: boolean;
   fallbackLang?: string | string[];
   failedRetries: number;
-  availableLangs: AvailableLangs;
+  availableLangs?: AvailableLangs;
   flatten: {
     aot: boolean;
   };
@@ -46,7 +46,7 @@
   interpolation: ['{{', '}}'],
 };
 
 type DeepPartial<T> = T extends Array<any>
   ? T
   : T extends object
   ? { [P in keyof T]?: DeepPartial<T[P]> }

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

@@ -102,7 +102,7 @@ export class TranslocoService implements OnDestroy {
   private cache = new Map<string, Observable<Translation>>();
   private firstFallbackLang: string | undefined;
   private defaultLang = '';
-  private availableLangs: AvailableLangs = [];
+  private availableLangs?: AvailableLangs;
   private isResolvedMissingOnce = false;
   private lang: BehaviorSubject<string>;
   private failedLangs = new Set<string>();
@@ -129,7 +129,7 @@ export class TranslocoService implements OnDestroy {
     service = this;
     this.config = structuredClone(userConfig);
 
-    this.setAvailableLangs(this.config.availableLangs || []);
+    this.setAvailableLangs(this.config.availableLangs);
     this.setFallbackLangForMissingTranslation(this.config);
     this.setDefaultLang(this.config.defaultLang);
     this.lang = new BehaviorSubject<string>(this.getDefaultLang());
@@ -169,7 +169,7 @@ export class TranslocoService implements OnDestroy {
     return this;
   }
 
-  setAvailableLangs(langs: AvailableLangs) {
+  setAvailableLangs(langs: AvailableLangs | undefined) {
     this.availableLangs = langs;
   }
 
@@ -181,7 +181,7 @@ export class TranslocoService implements OnDestroy {
    * depending on how the available languages are set in your module.
    */
   getAvailableLangs() {
-    return this.availableLangs;
+    return this.availableLangs ?? [];
   }
 
   load(path: string, options: LoadOptions = {}): Observable<Translation> {
@@ -626,7 +626,11 @@ export class TranslocoService implements OnDestroy {
    * @internal
    */
   _isLangScoped(lang: string) {
-    return this.getAvailableLangsIds().indexOf(lang) === -1;
+    const availableLangsIds = this.getAvailableLangsIds();
+    if (!availableLangsIds) {
+      return true;
+    }
+    return availableLangsIds.indexOf(lang) === -1;
   }
 
   /**
@@ -636,7 +640,11 @@ export class TranslocoService implements OnDestroy {
    * False if the given string is not an available language.
    */
   isLang(lang: string): boolean {
-    return this.getAvailableLangsIds().indexOf(lang) !== -1;
+    const availableLangsIds = this.getAvailableLangsIds();
+    if (!availableLangsIds) {
+      return true;
+    }
+    return availableLangsIds.indexOf(lang) !== -1;
   }
 
   /**
@@ -701,8 +709,12 @@ export class TranslocoService implements OnDestroy {
     return size(this.getTranslation(lang));
   }
 
-  private getAvailableLangsIds(): string[] {
-    const first = this.getAvailableLangs()[0];
+  private getAvailableLangsIds(): string[] | null {
+    const first = this.getAvailableLangs()?.[0];
+
+    if (isNil(first)) {
+      return null;
+    }
 
     if (isString(first)) {
       return this.getAvailableLangs() as string[];

libs/transloco/src/lib/types.ts

@@ -30,7 +30,7 @@ export interface LangDefinition {
   id: string;
   label: string;
 }
-export type AvailableLangs = string[] | LangDefinition[];
+export type AvailableLangs = string[] | LangDefinition[] | null;
 export interface SetTranslationOptions {
   merge?: boolean;
   emitChange?: boolean;