@angular/core

Inject

decorator

Parameter decorator on a dependency parameter of a class constructor that specifies a custom provider of the dependency.

API

@Inject(token: string); @Inject(token: any);

Usage Notes

The following example shows a class constructor that specifies a custom provider of a dependency using the parameter decorator.

When @Inject() is not present, the injector uses the type annotation of the parameter as the provider.

class Engine {} @Injectable() class Car { constructor(public engine: Engine) {} // same as constructor(@Inject(Engine) engine:Engine) } const injector = Injector.create({ providers: [ {provide: Engine, deps: []}, {provide: Car, deps: [Engine]}, ], }); expect(injector.get(Car).engine instanceof Engine).toBe(true);