Proper error handling for Angular 2 http result

Question

I've been using the http error handling strategy used in the angular.io documentation:

getHeroes () {
    return this.http.get(this._heroesUrl)
                    .map(res => <Hero[]> res.json().data)
                    .catch(this.handleError);
    }
    private handleError (error: Response) {
        console.error(error);
        return Observable.throw(error.json().error || 'Server error');
    }
}

In some scenarios, instead of a JSON response I will receive a 204 status code (No Data). In this case, the error handler doesn't get invoked until failing to parse the result via res.json(), so the error passed to handleError is "error.json is not a function".

How can I interrogate the response stream to check for a 200 (OK) status code or a response header content-type of "application/json", and signal an error handler with a more relevant error message?

Solution

http .get('Some Url') .map(res => { 
// If request fails, throw an Error that will be caught 
if(res.statu != 200) { 
throw new Error('This request has failed ' + res.status); } // If everything went fine, return the response 
else {return res.json(); 
} })

This may help you.

This is just for understanding how to use the status from the response, you can modify according to your requirement.

Error is thrown only for non 200 code check this commit