Ich lerne Angular2. In DI-Seiten gibt es Beispielcode zum Verspotten.https: //angular.io/docs/ts/latest/guide/dependency-injection.htm

Was bedeutet e

let mockService = <HeroService> {getHeroes: () => expectedHeroes }

Es sieht aus wie definierenmockService Funktion vonHeroService Funktion.

Was ist<HeroService>? Ist<HeroService> Casting?

let expectedHeroes = [{name: 'A'}, {name: 'B'}]
let mockService = <HeroService> {getHeroes: () => expectedHeroes }

it('should have heroes when HeroListComponent created', () => {
  let hlc = new HeroListComponent(mockService);
  expect(hlc.heroes.length).toEqual(expectedHeroes.length);
});