What it does
Configures the Injector to return a value by invoking a useFactory function.
How to use
1 2 3 | function serviceFactory() { ... }const provider: FactoryProvider = {provide: 'someToken', useFactory: serviceFactory, deps: []}; |
Interface Overview
1 2 3 4 5 6 | interface FactoryProvider { provide : any useFactory : Function deps : any[] multi : boolean} |
Interface Description
For more details, see the Dependency Injection Guide.
Example
1 2 3 4 5 6 7 8 9 10 11 12 | const Location = new OpaqueToken('location');const Hash = new OpaqueToken('hash');const injector = ReflectiveInjector.resolveAndCreate([ provide: Hash, useFactory: (location: string) => location.split('#')[1], deps: [Location] }]);expect(injector.get(Hash)).toEqual('someLocation'); |
Dependencies can also be marked as optional:
1 2 3 4 5 6 7 8 9 10 11 | const Location = new OpaqueToken('location');const Hash = new OpaqueToken('hash');const injector = ReflectiveInjector.resolveAndCreate([{ provide: Hash, useFactory: (location: string) => `Hash for: ${location}`, // use a nested array to define metadata for dependencies. deps: [[new Optional(), new Inject(Location)]]}]);expect(injector.get(Hash)).toEqual('Hash for: null'); |
Interface Details
provide : any
An injection token. (Typically an instance of Type or OpaqueToken, but can be any).
useFactory : Function
A function to invoke to create a value for this token. The function is invoked with resolved values of tokens in the deps field.
deps : any[]
A list of tokens which need to be resolved by the injector. The list of values is than used as arguments to the useFactory function.
multi : boolean
If true, than 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.
1 2 3 4 5 6 7 | const injector = ReflectiveInjector.resolveAndCreate([ {provide: 'local', multi: true, useValue: 'en'}, {provide: 'local', multi: true, useValue: 'sk'},]);const locales: string[] = injector.get('local');expect(locales).toEqual(['en', 'sk']); |
exported from @angular/core/index, defined in @angular/core/src/di/provider.ts
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