Dress Sia BlackButterfly Essence Purple Sia Satin Prom Satin BlackButterfly wZaaqx
Elegant Bridesmaid Dress Maxi Dress Back Dresses Evening Split Party Alicepub Purple Split Dress Maxi Evening Elegant Back Party Alicepub Dress Purple Dresses Bridesmaid

Dress Maxi Evening Party Dresses Bridesmaid Dress Purple Split Elegant Alicepub Back qgBOnOP

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