Angular DI : Injecting a value token into factory provider

Question

是否可以将 InjectionToken 注入(inject)工厂提供程序:

目前，我已经编码:

export const HOST_TOKEN = new InjectionToken<string>("host");

let configDataServiceFactory = (userService: UserService, host: string) => {
    return new Config("host", 8080, userService.getUser(), userService.getPasswd());
};

export let configDataServiceProvider =
{
    provide: CONFIG_API,
    useFactory: configDataServiceFactory,
    deps: [UserService, HOST_TOKEN]
};

进入我的模块:

@NgModule(
  providers: [
    {provide: HOST_TOKEN, useValue: "allianz-host"},
    configDataServiceProvider
  ]
)

然而， Angular 正在注入(inject) configDataServiceProvider值(value) "host" , 而不是 "host-allianz"
有任何想法吗？

Answer 1

是的，您可以使用 @Inject像下面这样的装饰器，它将帮助您从 DI 容器中提取相关的依赖项。

let configDataServiceFactory = (userService: UserService, @Inject(HOST_TOKEN) host: string) => {
    return new Config(host, 8080, userService.getUser(), userService.getPasswd());
};

您也可以考虑以下选项。基本上都注册了 InjectionToken可以从应用程序 Injector 中检索，可以通过调用 get 来实现方法超过 injector实例并通过 InjectorToken姓名。

export const HOST_TOKEN = new InjectionToken<string>("host");

let configDataServiceFactory = (userService: UserService, injector: Injector) => {
    let host = injector.get(HOST_TOKEN); //retrieved token from injector
    return new Config(host, 8080, userService.getUser(), userService.getPasswd());
};

export let configDataServiceProvider =
{
    provide: CONFIG_API,
    useFactory: configDataServiceFactory,
    deps: [UserService, Injector]
};

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