Angular2 - TypeError：this.http.get（...）。toPromise不是函数

Question

i try to follow tutorial on angular.io ( Tour the Heroes ) But instead of tutorial I try to make real GET request on some JSON.

My code looks like:

  private userUrl = 'https://jsonplaceholder.typicode.com/users';
  constructor(private http: Http) {}

  getUsersHttp(): Promise<User[]> {
    return this.http.get(this.userUrl)
      .toPromise()
      .then(response => response.json().data as User[])
      .catch(this.handleError);
  }

To service I import just few basic things:

import { Injectable }     from '@angular/core';
import { Headers, Http, Response } from '@angular/http';
import { User } from './user';

Where user.ts is basicly copy of heroe.ts in TOH so:

export class User {
  id: number;
  name: string;
}

How I call this specific method in service: First I try multiple things but while debugging i try just console.log it so:

 console.log(this.userService.getUsersHttp());

When page is loading in console i found multiple errors: First one is:

EXCEPTION: TypeError: this.http.get(...).toPromise is not a function

Second one is:

EXCEPTION: TypeError: this.http.get(...).toPromise is not a functionBrowserDomAdapter.logError @

Service it self looks fine. I added my service to app.module.ts in this line:

providers: [ HTTP_PROVIDERS, UserService ]

and it works if I directly return data with some function like (and comment out calling getUsertHttp function):

  getUsers() {
    return [{'id': 1, 'name': 'User1'}, {'id': 2, 'name': 'User2'}];
  }

I try to describe everything which may be important so sorry if question is kind long a bit. Please guys can you give me hint what i am doing wrong?

Answer 1

看起来你缺少导入：

import 'rxjs/add/operator/toPromise';