Example of lambda functions usage to create flexible ajax utility module

ajax-jquery-lambda.js

var _ = require('lodash');
var $ = require('jquery');

var apis = {
  main: '/api/v1/',
  tracker: '/tracking/v1/',
};

/**
 * Default data sent with every request;
 * can be overwritten per request using the same key name
 * @return {object} default data
 */
function defaultData () {
  return {
    _: (new Date()).getTime(),
  }
}

/**
 * Returns function which returns jquery deffered upon ajax request
 * @param  {string} APIRoot  root url of the API for relative url creation
 * @param  {string} type  request type(GET, POST...)
 * @param  {string} url  API endpoint. Appended to APIRoot
 * @return {function} data  gets sent with request
 */
function request (APIRoot, type, url) {
  return function (data) {
    return $.ajax({
      url: apis[APIRoot] + url,
      type: type,
      data: _.assign(defaultData(), data),
      dataType: 'json',
    });
  }

// main API requests
function xMain (type, url) {
  return request('main', type, url);
}

// tracker API requests
function xTracker(type, url) {
  return request('tracker', type, url);
}

module.exports = {
  app: {
    getBundle: xMain('GET', 'get-bundle'),
  },

  tracker: {
    getMostActiveUsers: xTracker('GET', 'most-active/users'),
  },
};