Callbacks

callback.js

function coordinates(x, y, callback) {
  callback(x, y);
}

coordinates(10, 20, function(x, y){ 
  console.log(x + y); 
});

jQuery.js

jQuery = {
  get: function(url, params, callback) {
    // DO XHR
    if(response.status === 200) {
      callback(response.data);
    }
  }
};

jQuery.get('/get/food', 'token:pizzahut', function(data) { 
  return data;
});