angular4 http请求怎么抓取错误信息

Question

this.http.get('http://...')
.map(res => res.json())
.subscribe(users => console.log(users));
请问这种写法怎么CatchError呢？

Answer 1

observable的subscription里面是可以接收三个callback的， onNext, onError, onComplete

this.http.get('http://...')
.map(res => res.json())
.subscribe(
(users: any) =>  { console.log(users) },
(error: Error) => { console.error(error)}, 
() => {}
);

Answer 2

this.http.get('http://...')
.map(res => res.json())
.subscribe(
   success => console.log(success),
   fail => console.log(fail)
);