Angular2: res.json is not a function

Question

I am trying to use the following service in my code:

import {Injectable} from '@angular/core';
import {Http,Response} from "@angular/http";
import 'rxjs/Rx';

@Injectable()
export class HttpService{
    constructor(private http : Http){}

    getData(){
      return  this.http.get("URI")
      .map( (res: Response) => res.json()  );
    }
}

The problem is, in run time it complains with:

res.json is not a function

I have defined the datatype of res as Response, but still complains

.map( (res: Response) => res.json()  ) 

if i replace the map with subscribe it works fine:

.subscribe( res =>{
                res.json();
                console.log("City is:"+ res.json().city.name)
            });

Answer 1

就其价值而言，在 Angular 5 中，我发现res.json is not a function错误，如果响应是纯 json，只需返回res即可修复。

Answer 2

Try to import 'rxjs/add/operator/map'; instead of import 'rxjs/Rx'; . That should fix the problem.

Answer 3

You Don't need to use this: .map((res: Response) => res.json() ); or .map(res => res.json()); because HttpClient.get() feeds or applies to res.json() automatically and returns Observable<HttpResponse<string>> .

You no longer need to call this function yourself again. Just simply put it this way: .map(res => res ); this resolves or solve the problem.

Answer 4

You do not need to call res.json() if you response is already a Json you can directly work with res you do not even need to use map in this case

  getData(){
  return  this.http.get("URI");
}

Answer 5

Try to put only like this

.map((response: Response) => response)

This work surely in Angular