interface
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[] }
Property | Description |
---|---|
provide: any | An injection token. (Typically an instance of |
multi?: boolean | When true, injector returns an array of instances. This is useful to allow multiple providers spread across many files to provide configuration information to a common token. |
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');
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']);
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Licensed under the Creative Commons Attribution License 4.0.
https://v12.angular.io/api/core/FactoryProvider