Long Dress Straps Bridesmaid Purple Formal Gown Wedding Women Cowl Sequin Lavender MACloth Back twBqaXw
Top Womens Tunic Long Shirt Boyfriend Down Grey Long Button Casual OFA AL Sleeve Casual Long Tunic Boyfriend Top Long Womens Button AL Shirt Grey Down Sleeve OFA

Grey Sleeve Button OFA Down Boyfriend Tunic Womens Casual Long Top AL Long Shirt 7UnBqg7

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