Angular 4依赖注入学习教程之ClassProvider的使用（三）

export interface ClassProvider {
 // 用于设置与依赖对象关联的Token值，Token值可能是Type、InjectionToken、
 // OpaqueToken的实例或字符串
 provide: any; 
 useClass: Type<any>;
 // 用于标识是否multiple providers，若是multiple类型，则返回与Token关联的依赖
 // 对象列表
 multi?: boolean; 
}

@NgModule({
 ...
 providers: [HeroService], // 方式一
 bootstrap: [AppComponent]
})
export class AppModule { }

// TypeProvider接口
export interface TypeProvider extends Type<any> {}

@NgModule({
 ...
 providers: [{
 provide: HeroService, useClass: HeroService // 方式二
 }],
 bootstrap: [AppComponent]
})
export class AppModule { }

export class MockHeroService {
 heros: Array<{ id: number; name: string }> = [
 { id: 16, name: 'RubberMan' },
 { id: 17, name: 'Dynama' },
 { id: 18, name: 'Dr IQ' },
 { id: 19, name: 'Magma' },
 { id: 20, name: 'Tornado' }
 ];

 getHeros() {
 return this.heros;
 }
}

@NgModule({
 ...
 providers: [{
 provide: HeroService, useClass: MockHeroService
 }],
 bootstrap: [AppComponent]
})
export class AppModule { }

ID: 16 - Name: RubberMan
ID: 17 - Name: Dynama
ID: 18 - Name: Dr IQ
ID: 19 - Name: Magma
ID: 20 - Name: Tornado

export interface Type<T> extends Function { new (...args: any[]): T; }

export function isType(v: any): v is Type<any> {
 return typeof v === 'function';
}