Map http error response [duplicate]

Question

Is there a way to map not only the successful response but also the error?

I want to get a modified error in the subscribe function

request.subscribe(
    response => {
        this.user = response;
    },
    error => {
        this.error = error;
    }
);

I already tried this

let request = this.http.put(url, JSON.stringify(user))
.map(
    response => response.json(),
    error => this.handleError(error) // returns a string
);

but handleError is never getting executed.

Thanks in advance.

Answer 1

To map the result of error response, you need to use the catch operator:

let request = this.http.put(url, JSON.stringify(user)).map(
            response => response.json())
          .catch(
            error => this.handleError(error)
        );

The callback specified in the map operator is only called for successful responses.

If you want to "map" the error, you could use something like that:

this.http.get(...)
       .map(...)
       .catch(res => Observable.throw(res.json())

In this case, the mapped error will be provided to the callback defined in the second parameter of the subscribe method.