javascript - 错误: Unreachable code detected ionic 3 weather app

Question

好的，所以我正在按照 ionic 3 上的遍历媒体教程进行操作，当我到达创建提供程序的部分时，我收到错误消息，指出此处检测到无法访问的代码:

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

它还在 typescript 上说

cannot find the name 'map' did you mean 'Map'?

import { HttpClient } from '@angular/common/http';
import { Injectable } from '@angular/core';
import 'rxjs/add/operator/map';

@Injectable()
export class WeatherProvider {
  apiKey = "89cca14f4ffcd27d602ad5e587f8e17f";
  url;

 constructor(public http: HttpClient) {
   console.log('Hello WeatherProvider Provider');
   this.url = "api.openweathermap.org/data/2.5/weather?q=";
 }



 getWeather(city, country){
 return this.http.get(this.url+city+','+country);
   .map((res: Response) => res.json() );
 }

}

Answer 1

getWeather() 中的 return 语句导致 .map() 无法访问。您应该将 return 语句设置为函数中的最后一个语句。