code: function (e, keyCode, mouseButton) {
  
          keyCode = keyCode || e.keyCode || e.button;
          var action = keyBindings[keyCode];
  
          // publish a message for keydown event
          me.event.publish(me.event.KEYDOWN, [
              action,
              keyCode,
              action ? !keyLocked[action] : true
          ]);
  
          if (action) {
              if (!keyLocked[action]) {
                  var trigger = (typeof mouseButton !== "undefined") ? mouseButton : keyCode;
                  if (!keyRefs[action][trigger]) {
                      keyStatus[action]++;
                      keyRefs[action][trigger] = true;
                  }
              }
              // prevent event propagation
              if (preventDefaultForKeys[keyCode] && (typeof e.preventDefault === "function")) {
                  // "fake" events generated through triggerKeyEvent do not have a preventDefault fn
                  return e.preventDefault();
              }
              else {
                  return true;
              }
          }
  
          return true;
      }
docs: key down event
  @ignore