How to trigger jquery.ajax() error callback based on server response, not HTTP 500?

Question

By using jquery ajax function, I can do something like:

$.ajax({

  url: url,
  type: \'GET\',
  async: true,
  dataType: \'json\',
  data: data,

 success:          


        

Answer 1

We presume the server is sending JSON, and in case of a successful request we'll get something like this:

{
    success: true,
    data: {
        name: 'Foo'
    }
}

... and on failure:

{
    success: false,
    error: 'Something bad happened.'
}

Then we simply filter the response with a $.Deferred:

$.get('http://localhost/api').then(function(res) {
    var filter = $.Deferred();

    if (res.success) {
        filter.resolve(res.data);
    } else {
        filter.reject(res.error);
    }

    return filter.promise();
}).done(function(data) {
    console.log('Name:',  data.name); // Outputs: Foo
}).fail(function(error) {
    console.log('Error:', error); // Outputs: Something bad happened.
})