Angular Dependency Injection

Version: Angular 21 (2025) Tags: DI, Services, Providers, Tokens, inject()

References: DI Guide • API • inject()

API Changes

This section documents recent version-specific API changes.

• NEW: Functional injection with inject() — Preferred over constructor injection in modern Angular source

• NEW: inject() with Optional decorator — inject(Service, { optional: true })

• NEW: inject() with SkipSelf — inject(Service, { skipSelf: true })

• NEW: Tree-shakable InjectionToken — new InjectionToken<T>(desc, { providedIn: 'root' })