如何在TypeScript中扩展一个类？

Question

我有几个服务，它们内部的代码相同：

 constructor (private http: Http) {
    //use XHR object
    let _build = (<any> http)._backend._browserXHR.build;
    (<any> http)._backend._browserXHR.build = () => {
        let _xhr =  _build();
        _xhr.withCredentials = true;
        return _xhr;
    };
}

我想把代码移动到单独的文件http_base_clas.ts中，并尽可能地重复使用代码。这是http_base_clas.ts:

import {Http} from '@angular/http';

export class HttpBaseClass {
    constructor ( http: Http) {
        //use XHR object
        let _build = (<any> http)._backend._browserXHR.build;
        (<any> http)._backend._browserXHR.build = () => {
            let _xhr =  _build();
            _xhr.withCredentials = true;
            return _xhr;
        };
    }
}

如何将 http_base_class 扩展到 auth_service.ts 中？

import {Injectable} from '@angular/core';
import {Http, Response} from '@angular/http';
import {Headers, RequestOptions} from '@angular/http';
import {Observable} from 'rxjs/Observable';

@Injectable ()

export class AuthenticationService {
result: {
    ok: boolean;
};
private verifyUrl = 'http:example.com;  

constructor (private http: Http) {

}
private authRequest (url) {
    let body = JSON.stringify({});
    let headers = new Headers({ 'Content-Type': 'application/json'});
    let options = new RequestOptions({
        headers: headers
    });
    return this.http.post(url, body, options)
        .map((res: Response) => res.json())
        .map(res => {
            this.result = res;
            return this.result.ok;
        });
    }
}

- Serhiy

Answer 1

class AuthenticationService extends HttpBaseClass {
  constructor(http:Http) {
    super(http);
  }

  private authRequest (url) {
    ...
  }
}

- Günter Zöchbauer