How to create an Http instance without using const

问题:

For some reason, I don't want to use constructor(private http: Http) DI.

Looked at https://angular.io/docs/ts/latest/api/http/index/Http-class.html

and tried

const injector = ReflectiveInjector.resolveAndCreate([
  BaseRequestOptions,
  XHRConnection,
  {
    provide: Http,
    useFactory: (backend, defaultOptions) => new Http(backend, defaultOptions),
    deps: [XHRConnection, BaseRequestOptions]
  }
]);

this.http = injector.get(Http);

Error says

ORIGINAL EXCEPTION: Cannot resolve all parameters for 'XHRConnection'(?, ?, ?). Make sure that all the parameters are decorated with Inject or have valid type annotations and that 'XHRConnection' is decorated with Injectable.

回答1:

You need to provide HTTP_PROVIDERS:

const injector = ReflectiveInjector.resolveAndCreate([
  HTTP_PROVIDERS,
  XHRConnection,
  {
    provide: Http,
    useFactory: (backend, defaultOptions) => new Http(backend, defaultOptions),
    deps: [XHRConnection, BaseRequestOptions]
  }
]);

回答2:

Actually, it can be as simple as

const injector = ReflectiveInjector.resolveAndCreate([
  HTTP_PROVIDERS
]);

this.http = injector.get(Http);

Based on Günter Zöchbauer's answer.