code: function (e) {
          // 点击菜单将触发这里
          
          const editor = this.editor
          const isSeleEmpty = editor.selection.isSelectionEmpty()
  
          if (isSeleEmpty) {
              // 选区是空的，插入并选中一个“空白”
              editor.selection.createEmptyRange()
          }
  
          // 执行 italic 命令
          editor.cmd.do('italic')
  
          if (isSeleEmpty) {
              // 需要将选取折叠起来
              editor.selection.collapseRange()
              editor.selection.restoreSelection()
          }
      }
docs: 点击事件