在VS forRoot中提供了Angular服务 [英] Angular service providedIn VS forRoot

问题描述

我想知道这两个代码块是否相等.

I'd like to know if these two blocks of code are equivalent or not.

我可以使用 providedIn 和 forRoot 相同的结果吗?

Can I use providedIn with the same result of forRoot?

@Injectable({
  providedIn: 'root'
})
export class MyService {
  constructor() { }
}

vs

@Injectable()
export class MyService {
  constructor() { }
}

@NgModule({
  imports: []
})
export class MyModule {
  static forRoot(): ModuleWithProviders {
    return {
      ngModule: MyModule,
      providers: [
        MyService
      ]
    };
  }
}

@NgModule({
  imports: [
    MyModule.forRoot()
  ],
  bootstrap: [AppComponent]
})
export class AppModule { }

[我仍将我的 MyModule 与 providedId 单例服务一起使用一次

[I would still keep my MyModule for single use with the providedId singleton services]

推荐答案

providedIn 将基于该值直接注入 service -如果它是'root'，它将直接注入根 module -这将帮助您停止在模块 [providers]

providedIn will directly injects the service based on the value - if its 'root' it will directly inject in root module - this will help you to stop adding your service in module [providers]

Angular将在 module 中注入服务-如果您使用的是惰性加载模块-Angular将在每次加载其他模块时创建新的注入器

Angular will inject the service in the module - If in case you are using Lazy loading modules - angular will create new injectors whenever you load other modules

如果您使用延迟加载，最好在模块上进行 forRoot()注入，并确保您的 service 不创建多个注入器

If you use Lazy loading is better to go with forRoot() injection on the modules and make sure your service doesn't create multiple injectors

希望这对您有帮助-编码愉快！！

Hope this helps you - Happy coding !!

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