javascript jquery when with promises code example

Example: jquery ajax promise

$.ajax({
    url: "/someurl",
    method: "GET",
    data: { 
      a: "a"
  })
  .done(function(data) {
    console.log('success callback 1', data) 
  })
  .done(function(data) {
    console.log('success callback 2', data) 
  })
  .fail(function(xhr) {
    console.log('error callback 1', xhr);
  })
  .fail(function(xhr) {
    console.log('error callback 2', xhr);
  });