Configures the Injector to return a value by invoking a useFactory function.

interface FactoryProvider extends FactorySansProvider {
  provide: any
  multi?: boolean

  // inherited from core/FactorySansProvider
  useFactory: Function
  deps?: any[]
}

See also

• "Dependency Injection Guide".

Properties

Usage notes

const Location = new InjectionToken('location');
const Hash = new InjectionToken('hash');

const injector = Injector.create({
  providers: [
    {provide: Location, useValue: 'https://angular.io/#someLocation'}, {
      provide: Hash,
      useFactory: (location: string) => location.split('#')[1],
      deps: [Location]
    }
  ]
});

expect(injector.get(Hash)).toEqual('someLocation');

Dependencies can also be marked as optional:

const Location = new InjectionToken('location');
const Hash = new InjectionToken('hash');

const injector = Injector.create({
  providers: [{
    provide: Hash,
    useFactory: (location: string) => `Hash for: ${location}`,
    // use a nested array to define metadata for dependencies.
    deps: [[new Optional(), Location]]
  }]
});

expect(injector.get(Hash)).toEqual('Hash for: null');

Multi-value example

const locale = new InjectionToken<string[]>('locale');
const injector = Injector.create({
  providers: [
    {provide: locale, multi: true, useValue: 'en'},
    {provide: locale, multi: true, useValue: 'sk'},
  ]
});

const locales: string[] = injector.get(locale);
expect(locales).toEqual(['en', 'sk']);