code: function _pickBestAction(key, modifiers, action) {
  
          // if no action was picked in we should try to pick the one
          // that we think would work best for this key
          if (!action) {
              action = _getReverseMap()[key] ? 'keydown' : 'keypress';
          }
  
          // modifier keys don't work as expected with keypress,
          // switch to keydown
          if (action == 'keypress' && modifiers.length) {
              action = 'keydown';
          }
  
          return action;
      }
docs: picks the best action based on the key combination
  
  @param {string} key - character for key
  @param {Array} modifiers
  @param {string=} action passed in