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StaticClassProvider

interface

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

interface StaticClassProvider extends StaticClassSansProvider {
  provide: any
  multi?: boolean

  // inherited from core/StaticClassSansProvider
  useClass: Type<any>
  deps: any[]
}

See also

Properties

Property Description
provide: any

An injection token. Typically an instance of Type or InjectionToken, but can be any.

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.

Usage notes

abstract class Shape { name !: string; }

class Square extends Shape {
  name = 'square';
}

const injector = Injector.create([{provide: Shape, useClass: Square, deps: []}]);

const shape: Shape = injector.get(Shape);
expect(shape.name).toEqual('square');
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 = Injector.create([
  {provide: FormalGreeting, useClass: FormalGreeting, deps: []},
  {provide: Greeting, useClass: FormalGreeting, deps: []}
]);

// The injector returns different instances.
// See: {provide: ?, useExisting: ?} if you want the same instance.
expect(injector.get(FormalGreeting)).not.toBe(injector.get(Greeting));

Multi-value example

const locale = new InjectionToken<string[]>('locale');
const injector = Injector.create([
  {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://angular.io/api/core/StaticClassProvider