Top Black s Women Mermaid Beaded Evening DKBridal Dresses Long Gowns Prom Party wCFPqn
Grape Asymmetrical Party Dress Women Short Chiffon Prom Gown Dress Bridesmaid Alicepub Gown Dress Chiffon Short Prom Women Party Bridesmaid Grape Alicepub Dress Asymmetrical

Gown Grape Short Dress Alicepub Asymmetrical Party Bridesmaid Women Dress Chiffon Prom wxnBzSqgPx

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