Angular DI：将价值代币注入工厂提供者

Question

是否可以将 InjectionToken 注入工厂提供程序：

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
  ]
)

尽管如此， angular 正在注入configDataServiceProvidervalue "host"，而不是"host-allianz"

有任何想法吗？

Answer 1

是的，您可以使用@Inject如下装饰器来做到这一点，这将帮助您从 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。基本上所有注册InjectionToken的都可以从应用程序中检索Injector，这可以get通过injector实例调用方法并传递InjectorToken名称来实现。

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]
};

文档在这里