jQuery Element Caching System

gistfile1.js

// Requires underscore or lodash for isUndefined()
var $cache = {};

/**
 * Returns the page title element and will set the page title element when it doesn't exist
 * @param {String} selector
 * @returns {jQuery}
 */
getElement: function getElement(selector) {
  if (typeof selector !== 'string') {
    throw new Error('Selector must be a string');
  }

  return (_.isUndefined($cache[selector])) ?  $cache[selector] = $(selector) : $cache[selector];
}