High Boots Zipper Heel Shoes Block PU Knee High Boots Grey Platform WEIYIKANG Heels Leather Women Fashion w6Axg1g
Womens Girdle Rope Thin for Shorts Belt Braid Dress Candy Waistband Color Black Belt Candy Black Dress Waistband Color for Womens Shorts Thin Rope Girdle Braid

Rope Dress for Womens Waistband Belt Shorts Color Braid Candy Thin Black Girdle 1ZAqxaTw

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