Stable Interface
What it does
Configures the Injector to return a value of another useExisting token.
How to use
1 | const provider: ExistingProvider = {provide: 'someToken', useExisting: 'someOtherToken'}; |
Interface Overview
1 2 3 4 5 | interface ExistingProvider { provide : any useExisting : 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 13 14 | class Greeting { salutation = 'Hello';}class FormalGreeting extends Greeting { salutation = 'Greetings';}const injector = ReflectiveInjector.resolveAndCreate( [FormalGreeting, {provide: Greeting, useExisting: FormalGreeting}]);expect(injector.get(Greeting).salutation).toEqual('Greetings');expect(injector.get(FormalGreeting).salutation).toEqual('Greetings');expect(injector.get(FormalGreeting)).toBe(injector.get(Greeting)); |
Interface Details
provide : any
An injection token. (Typically an instance of Type or OpaqueToken, but can be any).
useExisting : any
Existing token to return. (equivalent to injector.get(useExisting))
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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