在Angular 2中，response.json（）有什么作用？

Question

這是來自app / toh / hero.service.ts的angular 2 http指南：

...
@Injectable()
export class HeroService {
  private heroesUrl = 'app/heroes';  // URL to web API
  constructor (private http: Http) {}
  getHeroes (): Observable<Hero[]> {
    return this.http.get(this.heroesUrl)
                    .map(this.extractData)
                    .catch(this.handleError);
  }
  private extractData(res: Response) {
    let body = res.json();
    return body.data || { };
  }
  private handleError (error: Response | any) {
   ...
  }

}

請參考let body = res.json（）; 從API我在Response對象上找不到任何json（）方法。 從響應源我發現：

export var Body = (function () {
    function Body() {
    }
    /**
     * Attempts to return body as parsed `JSON` object, or raises an exception.
     */
    Body.prototype.json = function () {
        if (isString(this._body)) {
            return Json.parse(this._body);
        }
        if (this._body instanceof ArrayBuffer) {
            return Json.parse(this.text());
        }
        return this._body;
    };

這2個如何相關？

Answer 1

我查看了node_modules / @ angular / http / src並繼續搜索

export var響應

發現在文件static_response.js中。 它說：

export var Response = (function (_super) {
__extends(Response, _super);
function Response(responseOptions) {
    _super.call(this);
    this._body = responseOptions.body;
    this.status = responseOptions.status;
    this.ok = (this.status >= 200 && this.status <= 299);
    this.statusText = responseOptions.statusText;
    this.headers = responseOptions.headers;
    this.type = responseOptions.type;
    this.url = responseOptions.url;
}
Response.prototype.toString = function () {
    return "Response with status: " + this.status + " " + this.statusText + " for URL: " + this.url;
};
return Response;
}(Body));

在同一個文件中__extends的定義如下：

var __extends = (this && this.__extends) || function (d, b) {
    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
    function __() { this.constructor = d; }
    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};

所以Body有json（）＆Response通過復制從Body獲取它。

Answer 2

只需使用json（）映射您的響應

this.jsonp.get("http://localhost:8080/api/getpost") 
          .map(res => res.json()) 
          .subscribe(data => console.log(data));