Sequential Ajax Calls using jQuery

sequential.js

// parameters for ajax calls
var items = [
  { 'gender': 'male', 'nat': 'US' },
  { 'gender': 'female', 'nat': 'GB' }
];

// function to trigger the ajax call
var ajax_request = function(item) {
    var deferred = $.Deferred();

    $.ajax({
      url: 'https://randomuser.me/api/',
      dataType: "json",
      type: 'GET',
      data: item,
      success: function(data) {
        // do something here
        console.log(data.results[0]);
        // mark the ajax call as completed
        deferred.resolve(data);
      },
      error: function(error) {
        // mark the ajax call as failed
        deferred.reject(error);
      }
    });

    return deferred.promise();
  };

var looper = $.Deferred().resolve();

// go through each item and call the ajax function
$.when.apply($, $.map(items, function(item, i) {
  looper = looper.then(function() {
    // trigger ajax call with item data
    return ajax_request(item);
  });

  return looper;
})).then(function() {
  // run this after all ajax calls have completed
  console.log('Done!');
});