根据后台给一组id回显可选择的选项列表

  

<template>
  <div>
    <el-cascader
      :key="keyValue"
      ref="cascader"
      v-model="pids"
      :props="{ label: 'name', value: 'id' }"
      :options="options"
      clearable
      filterable
      @change="handleChange"
    />
    <button @click="clickHandle">回显[3,4,10]</button>
  </div>
</template>

<script>
export default {
  name: 'QualityClassify',
  data() {
    return {
      keyValue: 0,
      pids: [],
      options: [],
      defaultOptions: [
        {
          id: 1,
          name: '总部id1',
          children: [
            {
              id: 2,
              name: '工程技术部id2',
              parent_id: 1,
              children: [
                { id: 3, name: '工程员工id3', parent_id: 2 },
                { id: 4, name: '工程员工id4', parent_id: 2 },
                { id: 5, name: '工程员工id45', parent_id: 2 }
              ]
            },
            {
              id: 7,
              name: '人力资源id7',
              parent_id: 1,
              children: [
                { id: 8, name: '人力员工id8', parent_id: 7 },
                { id: 9, name: '人力员工id9', parent_id: 7 },
                { id: 10, name: '人力员工id10', parent_id: 7 }
              ]
            }
          ]
        }
      ],
      defaultArr: [[1, 2, 3], [1, 2, 4], [1, 7, 10]]
    }
  },
  watch: {
    options() {
      this.keyValue++
    }
  },
  methods: {
    handleChange(value) {
      console.log('value', value)
    },
    // 删除children为空
    deleteChildren(arr) {
      return arr.map(item => {
        if (item.children && item.children.length > 0) {
          this.deleteChildren(item.children)
        } else {
          delete item.children
        }
        return item
      })
    },
    clickHandle() {
      const list = []
      this.findParentChild(this.defaultOptions, this.defaultArr, list)
      this.options = this.deleteChildren(list)
    },
    // 根据id数组查找对应的对象数组
    findParentChild(list, str, arr) {
      list.map(v => {
        str.map(s => {
          s.filter(x => {
            if (x === v.id) {
              if ((!v.parent_id || v.parent_id !== '0') && arr.length > 0) {
                this.findChild(v, arr, str)
              } else {
                const isHas = arr.findIndex(x => x.id === v.id)
                if (isHas === -1) {
                  arr.push({
                    ...v,
                    children: []
                  })
                }
              }
            } else {
              if (v.children && v.children.length) {
                this.findParentChild(v.children, str, arr)
              } else {
                return false
              }
            }
          })
        })
      })
    },
    // 查找最终列表父级的children，并往里塞对象
    findChild(obj, arr, str) {
      arr.map(v => {
        if (v.children && v.children.length > 0) {
          const isHas = v.children.findIndex(x => x.id === obj.id)
          if (isHas === -1 && obj.parent_id === v.id) {
            v.children.push({
              ...obj,
              children: []
            })
          } else if (obj.children) this.findParentChild(obj.children, str, v.children)
        } else {
          if (obj.parent_id === v.id) {
            v.children.push({
              ...obj,
              children: []
            })
            if (obj.children) this.findParentChild(obj.children, str, v.children)
          }
        }
      })
    }
  }
}
</script>