diff --git a/lib/core/src/lib/auth/services/oidc-authentication.service.ts b/lib/core/src/lib/auth/services/oidc-authentication.service.ts
index 41d8c4c27f..7e0b85aeab 100644
--- a/lib/core/src/lib/auth/services/oidc-authentication.service.ts
+++ b/lib/core/src/lib/auth/services/oidc-authentication.service.ts
@@ -79,7 +79,7 @@ export class OidcAuthenticationService extends BaseAuthenticationService {
         return this.appConfig.oauth2.implicitFlow;
     }
 
-    isAuthCodeFlow() {
+    isAuthCodeFlow(): boolean {
         return this.appConfig.oauth2.codeFlow;
     }