const toggleOption = (option: CheckboxOptionType) => { const optionIndex = mergedValue.value.indexOf(option.value); const value = [...mergedValue.value]; if (optionIndex === -1) { value.push(option.value); } else { value.splice(optionIndex, 1); } if (props.value === undefined) { mergedValue.value = value; } const val = value .filter(val => registeredValues.value.has(val)) .sort((a, b) => { const indexA = options.value.findIndex(opt => opt.value === a); const indexB = options.value.findIndex(opt => opt.value === b); return indexA - indexB; }); emit('update:value', val); emit('change', val); formItemContext.onFieldChange(); };这段代码中的emit作用，谢谢

`emit` 是 Vue.js 中的一个方法，用于触发一个自定义事件。在这段代码中，`emit('update:value', val)` 触发了一个名为 `update:value` 的自定义事件，并把参数 `val` 传递给该事件的回调函数。同时，`emit('change', val)` 也触发了一个名为 `change` 的自定义事件，并把参数 `val` 传递给该事件的回调函数。这样，当复选框选中状态发生变化时，就会触发这两个自定义事件，从而通知其他组件或父组件进行相应的处理。

相关问题

优化此代码 const openKeys = ref<string[]>([]) const selectedKeys = ref<string[]>([]) const { currentMenu, currentMenuTree, currentMenuList } = storeToRefs( useLayoutStore(), ) const rootSubmenuKeys = currentMenuList.value.filter((v: any) => { if (v.type === 0) { return v.parentId } }) watch( () => currentMenu, () => { openKeys.value = [currentMenu.value?.parentId] selectedKeys.value = [currentMenu.value?.id] }, { immediate: true }, ) const router = useRouter() /** * 点击事件 * @param e 事件对象 */ const handleClick = (e: any) => { const item = currentMenuList.value.find((_) => _.id === e.key) if (item) { router.push(item.path) } } /** * SubMenu 展开/关闭的回调 * @param e 展开的openKeys */ const onOpenChange = (e: any) => { const latestOpenKey = e.find((key: any) => openKeys.value.indexOf(key) === -1) if (rootSubmenuKeys.indexOf(latestOpenKey) === -1) { openKeys.value = e } else { openKeys.value = latestOpenKey ? [latestOpenKey] : [] } }

There are a few optimizations that could be made to this code:

1. Instead of using `ref` for `openKeys` and `selectedKeys`, you can use `reactive` to make the code more concise:

   const state = reactive({
     openKeys: [],
     selectedKeys: [],
   })

2. Instead of using `storeToRefs` to convert the store state to refs, you can use the `toRefs` function, which is shorter and more concise:

   const { currentMenu, currentMenuTree, currentMenuList } = toRefs(useLayoutStore())

3. Instead of using `watch` to watch the `currentMenu` state changes, you can use a computed property to update the `openKeys` and `selectedKeys` arrays:

   const selectedMenu = computed(() => {
     const item = currentMenuList.value.find((_) => _.id === currentMenu.value?.id)
     return [item?.id] || []
   })

   const parentMenu = computed(() => {
     const item = currentMenuList.value.find((_) => _.id === currentMenu.value?.parentId)
     return [item?.id] || []
   })

   watch([selectedMenu, parentMenu], ([selected, parent]) => {
     state.selectedKeys = selected
     state.openKeys = parent
   })

4. Instead of using `router.push` in the `handleClick` function, you can use the `router.push` method directly in the template:

   <Menu.Item :key="item.id" :to="item.path">{{ item.name }}</Menu.Item>

5. Finally, instead of using `rootSubmenuKeys` to filter the list of menu items, you can use a computed property to filter the list of menu items based on their type:

   const subMenuItems = computed(() => {
     return currentMenuList.value.filter((v: any) => v.type === 0 && v.parentId)
   })

By applying these optimizations, the code can be simplified and made more concise.

const getClassifyData = ()=>{ let pararms = {name: nodeLable.value} getClassify(pararms).then(res=>{ TypeSelects.value = res.result if(parId.value){ return getClassify({classId:parId.value}) } }).then(res=>{ childOptions.value = res.result if(claId.value){ return getClassify({ indexId: claId.value }) } }).then(res=>{ lastResult.value = res.result tableData.value = res.result.map(obj => { const dashIndex = obj.indexFinalName.indexOf("-"); const dataType = obj.indexFinalName.substring(0, dashIndex) + "-基础数据"; return { ...obj, dataType }; }) }).catch(error=>{ console.log('error', error) }) }改进代码

这段代码可以进行一些改进，例如：

1. 使用 async/await 替代 Promise 的 then() 和 catch() 方法，使代码更易读。

2. 将函数参数改为传入 pararms 对象，使代码更灵活。

3. 使用 try/catch 捕获错误，而不是使用 catch() 方法。

改进后的代码如下：

const getClassifyData = async (params) => {
  try {
    const res1 = await getClassify({ name: params.name });
    TypeSelects.value = res1.result;
    
    if(params.parId){
      const res2 = await getClassify({ classId: params.parId });
      childOptions.value = res2.result;
      
      if(params.claId){
        const res3 = await getClassify({ indexId: params.claId });
        lastResult.value = res3.result;
        
        tableData.value = res3.result.map(obj => {
          const dashIndex = obj.indexFinalName.indexOf("-");
          const dataType = obj.indexFinalName.substring(0, dashIndex) + "-基础数据";
          return { ...obj, dataType };
        });
      }
    }
  } catch (error) {
    console.log('error', error);
  }
}

这样就可以更简洁地实现同样的功能，并且代码更易读。