@angular/core

StaticClassProvider

interface

stable

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

API

  interface StaticClassProvider extends StaticClassSansProvider {}

provide

any

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

multi

boolean | undefined

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.

useClass

Type<any>

An optional class to instantiate for the token. By default, the provide class is instantiated.

deps

any[]

A list of tokens to be resolved by the injector. The list of values is then used as arguments to the useClass constructor.

Usage Notes

abstract class Shape { name!: string; } class Square extends Shape { override name = 'square'; } const injector = Injector.create({ providers: [{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 { override salutation = 'Greetings'; } const injector = Injector.create({ providers: [ {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({ providers: [ {provide: locale, multi: true, useValue: 'en'}, {provide: locale, multi: true, useValue: 'sk'}, ], }); const locales: string[] = injector.get(locale); expect(locales).toEqual(['en', 'sk']);