code: function(id, key) {
        // if key is defined and of type string....
        if(typeof key !== 'undefined' && typeof key === 'string') {
  
          // if id/key exists...
          if(memStore[id] && memStore[id][key]) {
            delete memStore[id][key];
          }
  
          return true;
        }
  
        // else if key is not defined...
        else if(typeof key === 'undefined') {
          delete memStore[id];
          return true;
        }
  
        // else key defined, but not of type string...
        else {
          throw new Error('invalid data type or missing value');
          return false;
        }
      }
docs: Forget a key or entire store.
  
  @function
  @param {String} id
  @param {String} [key] - Optional key value to forget. If key is not passed, id is removed.
  @returns {Boolean}