code: function(event) {
              // ignore if modifer keys pressed
              if(event.ctrlKey || event.shiftKey || event.altKey || event.metaKey){
                  return true;
              }
              var keyCode = event.keyCode;
              var action = this.getActionFromKeyCode(keyCode);
              // if no action bound to this keycode resolve the keydown event normally
              if (action === false) {
                  return true;
              }
              // call onKeyAction callback with the action matched
              this.onKeyAction(action);
  
              // cancel default browser keypress behavior
              event.preventDefault();
              return false;
          }
docs: Event handler for document.addEventListener('keydown', this). Triggered when a key is pressed.
  If an action is bound to the key pressed, false is returned to cancel the default browser behavior of the keypress.
  If an action is not bound to the key pressed, true is returned allowing the default browser behavior of the keypress to function.
  @method handleEvent
  @param {Object} event - The onkeydown event.
  @return bool