How to pass a default value with @Optional in Angular 20?

Question

In Angular 20, how can we inject an optional InjectionToken with a default value?

In Angular <20, I used to do it as follows:

constructor(@Optional@Inject(FOO) private foo = true){}

jonrsharpe · Accepted Answer · 2025-07-07 15:41:49Z

2

With DI using the inject function this is quite straightforward:

export class MyComponent {
  config = inject(FOO, { optional: true }) ?? true;
}

Note: thanks to JSON Derulo for their answer on GitHub.

edited Jul 7 at 15:41

jonrsharpe

123k31 gold badges277 silver badges488 bronze badges

answered Jul 7 at 15:32

Raphaël Balet

9,0998 gold badges65 silver badges118 bronze badges

Sign up to request clarification or add additional context in comments.

1 Answer 1