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API > @angular/core

ConstructorProvider

配置此 Injector，以返回令牌的实例。

Configures the Injector to return an instance of a token.

      
      interface ConstructorProvider extends ConstructorSansProvider {
  provide: Type<any>
  multi?: boolean

  // 继承自 core/ConstructorSansProvider
  deps?: any[]
}

参见

属性

属性说明
provide: Type<any>

注入令牌。通常是 Type 或 InjectionToken 的实例，但也可以是 any 实例。

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

multi?: boolean

如果为 true，则注入器返回实例数组。这对于允许多个提供者散布在多个文件中，以向某个公共令牌提供配置信息很有用。

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.

使用说明

      
      class Square {
  name = 'square';
}

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

const shape: Square = injector.get(Square);
expect(shape.name).toEqual('square');
expect(shape instanceof Square).toBe(true);

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']);