jQuery.selectorCache (credit: https://ttmm.io/tech/selector-caching-jquery/)

jquery-selector-cache.js

/* Usage: $.selectorCache('#element')
 *  or to refresh cache: $.selectorCache('#element', true)
 *
 * Credit: https://ttmm.io/tech/selector-caching-jquery/
 */

(function($){
  var debug = false;
  function SelectorCache() {
      var collection = {};
      function getFromCache( selector, refresh ) {
          if(undefined === refresh) refresh = false;
          if (undefined === collection[ selector ] || refresh) {
              collection[ selector ] = $( selector );
              if (debug && window.console) window.console.log('Cache created for: ' + selector);
          } else {
              if(debug && collection[selector].length > 0) {
                  if (window.console) window.console.log('Cache hit for: ' + selector);
              }
          }
          if(debug && collection[selector].length == 0){
              if(window.console) window.console.log('Element does not exist: '+selector);
          }
          return collection[ selector ];
      }
      return { get: getFromCache };
  }
  
  var selectorCache = new SelectorCache();
  
  $.selectorCache = function(selector, refresh) {
    return selectorCache.get(selector, refresh);
  };
}(jQuery));