code: function(callback) {
                  var _this = this
  
                  var initStorage = function() {
                      var obj = JSON.stringify([])
                      var _set = {}
                      _set[_this.key] = obj
                      storage.set(_set)
  
                      obj = JSON.parse(obj)
  
                      return obj
                  }
  
                  storage.get(this.key, function(items) {
                      var obj
                      if (Object.keys(items).length > 0) {
                          for (itemKey in items) {
                              obj = items[itemKey]
                              if (obj) {
                                  obj = JSON.parse(obj)
                              }
  
                              if (obj === null || typeof obj === 'undefined') {
                                  obj = initStorage()
                              } 
                              
                              if (callback) {
                                  callback(obj)
                              }
                          }
                      } else {
                          obj = initStorage()
                          callback(obj)
                      }
                  })
              }
docs: returns the index