Dress V3836 Bridal s Ivory Gown Beaded Wedding Ball David Lace Tulle Style WHZn86c6qv
Halloween Slogan Tee White Bones Funny Halloween Funny Lazy Womens Joke Slogan Womens Funny Bones Funny Lazy Joke Halloween Tee Halloween White

Funny Joke Womens Halloween Funny Slogan Bones Tee Lazy Halloween White HTqUw

A constructor parameter decorator that marks a dependency as optional.

See also

Description

The DI framework provides null if the dependency is not found. For example, the following code allows the possibility of a null result:

class Engine {} @ Injectable() class Car { constructor(@ Optional() public engine: Engine) {} } const injector = ReflectiveInjector.resolveAndCreate([Car]); expect(injector.get(Car).engine).toBeNull();
      
      class Engine {}

@Injectable()
class Car {
  constructor(@Optional() public engine: Engine) {}
}

const injector = ReflectiveInjector.resolveAndCreate([Car]);
expect(injector.get(Car).engine).toBeNull();
    

Options