Organizing AJAX calls by using a very simple inheritance structure and jQuery extend.

model.js

function Model(){}

// Converts a hash or each hash of an array into an instance of the calling class.
Model.fromObject = function(obj){
  if (obj && !$.isArray(obj)){
    return $.extend(new this(), obj);
  }

  var collection = [];
  for(var index in obj){ collection.push(this.fromObject(obj[index])); }
  return collection;
}

// Get a copy of all model attributes and values.
Model.prototype.serialize = function(){
  var obj = {};
  for (var key in this) {
    if (this.hasOwnProperty(key)) {
      obj[key] = this[key]
    }
  }
  return obj;
}

usage.js

// Find a single user with an id of 1
// Change the name and email and save the changes.

User.find(1).then(function(user){
  user.name = "Joshua";
  user.email = "jkappers@kalkomey.com";
  user.update();
});

user.js

// Define the model
function User() {}

// Mix Model class methods into the User model.
$.extend(User, Model);

// Prototypically inherit instance methods of Model
User.prototype = new Model();

// Get a list of all users.
User.all = function(){
  return $.getJSON('/users')
    .then(function(response){
      return User.fromObject(response);
    });
}

// Find a single user by id.
User.find = function(id) {
  var url = '/users/' + id;
  return $.getJSON(url)
    .then(function(response){
      return User.fromObject(response);
    });
}

// Update a user
User.prototype.update = function() {
  var url = '/user/' + this.id,
      data = this.serialize();

  return $.ajax({
    url: url,
    type: 'PUT',
    data: data
  });
}