Angular 2 - api调用后没有数据

Question

我正在玩角度2和英雄教程。问题是，无论我打电话给哪个api，我总是得到一个空的对象。

以下是代码：

app.compomnent.ts

import { Component, OnInit }         from '@angular/core';
import { Http, Response } from '@angular/http';

// Add the RxJS Observable operators we need in this app.
import './rxjs-operators';

@Component({
  selector: 'my-app',
  template: `
    <h1>Test</h1>
  `
})
export class AppComponent implements OnInit {

  constructor(private http: Http) {}

  private error: any;

  ngOnInit() {

    var request = this.http.get('http://date.jsontest.com');

    console.log("Request: " + request);
    console.log("Map: " + request.map(res => res));

    console.log("Complete: " + this.http.get('http://date.jsontest.com')
        .map(res => res.json())
        .catch(this.error));
  }
}

main.ts：

// The usual bootstrapping imports
import { bootstrap }      from '@angular/platform-browser-dynamic';
import { HTTP_PROVIDERS } from '@angular/http';

import { AppComponent }   from './app.component';

bootstrap(AppComponent, [
    HTTP_PROVIDERS
]);

我的控制台中的结果：

Answer 1

Observable在您订阅它之前不会做任何事情，因为它们很懒惰

  ngOnInit() {
    this.http.get('http://date.jsontest.com')
        .map(res => res.json())
        .subscribe(
           data => this.data = data,
           () => console.log('done'),
           err => this.error(err));
  }