Angular2:类型对象上不存在json [英] Angular2: json does not exist on type object

问题描述

我是初学者.我无法解决此问题.我已经阅读了其他错误，但仍然无法理解.

I am beginner. I am not able to solve this problem. i have read the other errors but still i am not able to understand.

我在执行.map或.subscribe服务时，会给我类似 类型对象上不存在属性'json'的错误.

While i am doing .map or .subscribe to the service it gives me error like Property 'json' does not exist on type object.

这是我的:continents.component.ts

import { Component, OnInit } from '@angular/core';  
import { DataContinentsService } from '../../services/dataContinents.service';
import 'rxjs/add/operator/map';  
@Component({  
selector: 'app-continents',  
templateUrl: './continents.component.html',  
styleUrls: ['./continents.component.css'],  
providers: [DataContinentsService]  
})  
export class ContinentsComponent implements OnInit {  
continent: any;  
constructor(private dataContinentService: DataContinentsService) { }  
public getContinentInfo() {  
this.dataContinentService.getContinentDetail()  
.map((response) => response.json())  
.subscribe(res => this.continent = res.json()[0]);  
}  
ngOnInit() {}  
}  

这是我的服务:DataContinentsService

import { Injectable } from '@angular/core';  
import {HttpClientModule, HttpClient} from '@angular/common/http';  
// import 'rxjs/add/operator/map';  
@Injectable()  
export class DataContinentsService {  
constructor(private _http: HttpClient) {}  
public getContinentDetail() {  
const _url = 'http://restcountries.eu/rest/v2/name/india?fulltext=true';  
return this._http.get(_url);  
}  
} 

这是我的模板:continents.component.html

<h1>Continents</h1>  
<h3>Name: {{continent.name}}</h3>  
<h3>Capital: {{continent.capital}}</h3>  
<h3>Currency: {{continent.currencies[0].code}}</h3>  
<button (click)="getContinentInfo()">get details</button>  

推荐答案

我猜测您正在阅读一些过时的文档. 旧的Http类用于返回确实具有json()方法的响应.

I'm guessing that you've been reading some outdated documentation. The old Http class used to return a response that did have a json() method.

旧的Http类已经淘汰，您现在可以正确使用HttpClient类. HttpClient的get()方法返回任何一个Observable-将响应的json映射为您的对象.通常，您将指定对象的类型，如下所示:

The old Http class has been retired, and you are now properly using the HttpClient class. HttpClient's get() method returns an Observable of any - it maps the response's json to an object for you. Typically, you'd specify the type of the object, like so:

   this.http.get<SomeObject>(url);

取而代之的是，您仅获得一个对象. 无论哪种情况，返回的对象都没有json()方法.

In lieu of that, you just get an Object. In either case, there's no json() method on the returned object.

因此，您的服务应执行以下操作:

So, your service should do this:

public getContinentDetail(): Observable<Continent[]> {  
  const _url = 'http://restcountries.eu/rest/v2/name/india?fulltext=true';  
  return this._http.get<Continent[]>(_url);  
}

您应该订阅这样的内容

this.dataContinentService.getContinentDetail().subscribe(continents: Continent[] => 
  this.continent = continents[0]);  
}  

这篇关于Angular2:类型对象上不存在json的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！