Dress Piece Short Dress Prom Chupeng Homecoming Black Crystal Halter Party Two XSCqwxU
Hollowed Sleeve Swing Poque Short Vintage Combed Dresses Cocktail Belle Women Cotton 2 Bp008 Combed Cocktail Dresses Short 2 Vintage Bp008 Hollowed Swing Poque Sleeve Women Cotton Belle

Belle Cocktail Sleeve Dresses 2 Poque Vintage Cotton Hollowed Women Swing Short Combed Bp008 rIgR1r

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