/Angular 2 TypeScript


Stable Interface

What it does

Configures the Injector to return an instance of useClass for a token.

How to use

class MyService {}

const provider: ClassProvider = {provide: 'someToken', useClass: MyService};

Interface Overview

interface ClassProvider {
  provide : any
  useClass : Type<any>
  multi : boolean

Interface Description

For more details, see the Dependency Injection Guide.


abstract class Shape { name: string; }

class Square extends Shape {
  name = 'square';

const injector = ReflectiveInjector.resolveAndCreate([{provide: Shape, useClass: Square}]);

const shape: Shape = injector.get(Shape);
expect(shape instanceof Square).toBe(true);

Note that following two providers are not equal:

class Greeting {
  salutation = 'Hello';

class FormalGreeting extends Greeting {
  salutation = 'Greetings';

const injector = ReflectiveInjector.resolveAndCreate(
    [FormalGreeting, {provide: Greeting, useClass: FormalGreeting}]);

// The injector returns different instances.
// See: {provide: ?, useExisting: ?} if you want the same instance.

Interface Details

provide : any

An injection token. (Typically an instance of Type or OpaqueToken, but can be any).

useClass : Type<any>

Class to instantiate for the token.

multi : boolean

If true, then 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 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

© 2010–2017 Google, Inc.
Licensed under the Creative Commons Attribution License 4.0.