角度4 ngModule有条件地注入提供者/服务

Question

在我的app.module.ts

中

@NgModule({
...
providers: [MyService,
          // providers used to create fake backend
          fakeBackendProvider,
          MockBackend,
          BaseRequestOptions
         ],
bootstrap: [AppComponent]
})

fakeBackendProvider，MockBackend和BaseRequestOptions用于模拟后端。有没有办法通过environment.ts文件中的变量注入这些服务？

Answer 1

你可以像这样使用它。创建了Plunker

//route to environment file
import { environment } from '../../environments/environment';
providers: [MyService,
          // providers used to create fake backend
     {
      provide: SomeSerivce,
      useFactory: authHeadersFactory
    },       
   ],


export function authHeadersFactory() {
  if (environment.prod) {
    return new Mock();
  }
  return new fakeBackend();
}