Traditonal Facioun Ethnic Partywear Indian Kameez Salwar Designer Da Maroon Women YwqX4dxdS
Midi Long Turtleneck Women Tight Pencil Sleeve Stretchy ALAIX Dress Grey Bodycon Sexy Tight Dress Turtleneck Women Grey ALAIX Bodycon Sexy Pencil Sleeve Stretchy Midi Long

ALAIX Sleeve Women Long Grey Stretchy Turtleneck Pencil Bodycon Midi Dress Sexy Tight IxIHwBr

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