How to encapsulate Vue3 Element-plus and el-menu unlimited menu components

The el-menu component provided to us in element can achieve up to three levels of nesting. If there is one more layer of data, you can only add one layer by yourself through variables. If you add two or three layers, it is often OK. It doesn't work, so we can only encapsulate it

Rendering

1. Define the data

MenuData.ts

export default [
    {
        id: "1",
        name: "第一级菜单",
        level: '1',
        child: [
            {
                id: "11",
                name: "第二级菜单",
                level: '1-1',
                child: [
                    {
                        id: "111",
                        name: "第三级菜单",
                        level: '1-1-1',
                        child: [
                            {
                                id: "1111",
                                name: "第四级菜单",
                                level: '1-1-1-1',
                                child: [
                                    {
                                        id: "11111",
                                        name: "第五级菜单",
                                        level: '1-1-1-1-1',
                                        child: []
                                    }
                                ]
                            }
                        ]
                    }]
            }
        ]
    },
    {
        id: "2",
        name: "第一级同级菜单",
        level: '2',
        child: []
    }
 
]

2. Encapsulation components

Encapsulation ideas:

1. Recycle your own components. If there is a subset, use your own components to pass the child data to yourself

2. If there is no subset, use el-menu-item

The following code implements the setup() function and setup syntax sugar respectively

setup syntax sugar

<template>
  <el-menu
    :default-active="defaultActive"
    :unique-opened="true"
    class="el-menu-vertical-demo"
  >
    <template v-for="item in menu">
      <!-- 如果有子集 -->
      <template v-if="item.child && item.child.length > 0">
        <el-sub-menu
          :key="item.id"
          :index="item.level"
          :disabled="item.meta?.disabled"
          :popper-append-to-body="false"
        >
          <template #title>
            <i :class="[item.meta?.icon]"></i>
            <!-- 添加空格 表示下级-->
            <span> {{ generateSpaces(item.level) }} </span>
            <span slot="title"> {{ item.name }}</span>
          </template>
          <MenuTree
            :menu="item.child"
            :defaultActive="defaultActive"
            @clickItem="clickItemHandle"
          />
        </el-sub-menu>
      </template>
      <!-- 如果没有子集 -->
      <template v-else>
        <el-menu-item
          :key="item.id"
          :index="item.level"
          :disabled="item.meta?.disabled"
          :popper-append-to-body="false"
          @click="clickItemHandle(item)"
        >
          <i :class="[item.meta?.icon]"></i>
          <!-- 添加空格 表示下级-->
          <span> {{ generateSpaces(item.level) }} </span>
          <span slot="title">{{ item.name }}</span>
        </el-menu-item>
      </template>
    </template>
  </el-menu>
</template>
 
<script lang="ts" name="MenuTree" setup>
// 把下面代码变成setup语法糖的形式 
import type { PropType } from "vue";
import type { MenuItem } from "@/types/lesson";
// type 为了方便写成这样 可以根据自己项目设定type
 defineProps({
  menu: {
    type: Array as unknown as PropType<any[]>,
    required: true,
    default: () => [],
  },
  defaultActive: {
    type: String as unknown as PropType<string>,
    required: true,
    default: [],
  },
});
 
const emit = defineEmits(["update-active-path", "clickItem"]);
 
// 返回的空格字符串 用于显示菜单层级 
const generateSpaces = (level: string) => {
  let str = "";
  level.split("")  .filter((it) => it != "-") .forEach(() => {
      str += "　";
  });
  return str;
};
 
// 点击当前菜单项
const clickItemHandle = (item: MenuItem) => {
  emit("clickItem", item);
};
</script>
 
<style scoped lang="less">
.el-menu {
  width: 288px;
}
</style>

setup function

<template>
  <el-menu :default-active="defaultActive"  :unique-opened="true"   class="el-menu-vertical-demo"  >
    <template v-for="item in menu">
        <template v-if="item.child && item.child.length > 0">
          <el-sub-menu 
            :key="item.id"
            :index="item.level"
            :disabled="item.meta?.disabled"
            :popper-append-to-body="false"
          >
            <template #title>
              <i :class="[item.meta?.icon]"></i>
              <!-- 添加空格 表示下级-->
              <span> {{ generateSpaces(item.level) }} </span>
              <span slot="title"> {{ item.name }}</span>
            </template>
            <MenuTree :menu="item.child" :defaultActive="defaultActive"  @clickItem="clickItemHandle"  />
          </el-sub-menu>
        </template>
        <template v-else>
          <el-menu-item 
            :key="item.id"
            :index="item.level"
            :disabled="item.meta?.disabled"
            :popper-append-to-body="false"
            @click="clickItemHandle(item)"
          >
            <i :class="[item.meta?.icon]"></i>
            <!-- 添加空格 表示下级-->
            <span> {{ generateSpaces(item.level) }} </span>
            <span slot="title">{{ item.name }}</span>
          </el-menu-item>
        </template>
      </template>
  </el-menu>
</template>
 
<script lang="ts">
import { defineComponent, toRefs } from &#39;vue&#39;;
import type { PropType } from &#39;vue&#39;
import type {MenuItem} from &#39;@/types/lesson&#39;
export default defineComponent({
  name: &#39;MenuTree&#39;,
  props: {
    menu: {
      type: Array as unknown as PropType<any[]>,
      required: true,
      default: () => [],
    },
    defaultActive: {
      type: String as unknown as PropType<string>,
      required: true,
      default: &#39;&#39;,
    },
  },
  emits: [&#39;update-active-path&#39;,&#39;clickItem&#39;],
  setup(props, context) {
    const { menu, defaultActive } = toRefs(props);
 
    const generateSpaces = (level:string) => {
      let str = &#39;&#39;
      level.split(&#39;&#39;).filter(it=>it!=&#39;-&#39;).forEach(() => {
        str += &#39;　&#39;
      })
      return str
    }
 
    const clickItemHandle = (item:MenuItem) => {
      context.emit(&#39;clickItem&#39;, item)
    }
 
   
    return {
      clickItemHandle,
      menu,
      defaultActive,
      generateSpaces,
    }
  },
});
</script>
 
<style scoped lang="less">
  .el-menu {
    width: 288px;
  }
</style>

type will not be added. It can be defined according to your own project and can be temporarily changed to any

3. Use components

<template>
 <MenuTree
        :menu="menuList"
        :defaultActive="defaultActive"
        @clickItem="handleMenuClick"
        :update-click="handleMenuClick"
      />
</template>
 
<script setup lang="ts">
import MenuTree from "./components/MenuTree.vue";
import type {MenuItem} from &#39;@/types/lesson&#39;
import menuData from &#39;./MenuData&#39;
 
const defaultActive = ref<string>(&#39;&#39;); // "1-1-1-1" 默认选中的数据
const menuList = ref(menuData)
 
const handleMenuClick = (item:MenuItem) => {
  console.log(&#39;父组件&#39;,item);
};
</script>

to supplement default -active variable, if you want to click on the first layer of data by default at the beginning, you need to find a pattern

Get all the levels, and return them to you through the interface to get all the levels. OK

For example, data format:

let arr = [  "1-1",
  "1-1-1",
  "1-1-1-1",
  "1-1-1-2",
  "1-1-1-3",
  "1-1-1-4",
  "1-1-1-5",
  "1-1-1-6",
  "1-1-2",
  "1-1-2-1"
]

The desired result is the longest element with the most identical numbers 1-1-1-1

arr.sort((a,b)=> b.split('-').length - a.split('-').length)[0]

Use split to prevent some The string is 10 and 11 two-digit

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