element-ui tree 设置成单选，并且父级不可选

<el-tree
    :data="date"
    show-checkbox
    node-key="moduldCode"
    ref="tree"
    check-strictly
    :highlight-current=‘true‘
    :check-on-click-node="true"
    :accordion="true"
    :default-checked-keys="[checkedkey]"
    :props="defaultProps"
    :default-expand-all="true"
    @check-change="parentModules"
  ></el-tree>

data() {
    return {
      date: [{
          moduldCode: 1,
          moduleName: ‘一级 2‘,
          disabled:true,
          child: [{
            moduldCode: 3,
            moduleName: ‘二级 2-1‘,
            disabled:true,
            child: [{
              moduldCode: 4,
              moduleName: ‘三级 3-1-1‘
            }, {
              moduldCode: 5,
              moduleName: ‘三级 3-1-2‘,
            }]
          }, {
            moduldCode: 2,
            moduleName: ‘二级 2-2‘,
            disabled:true,
            child: [{
              moduldCode: 6,
              moduleName: ‘三级 3-2-1‘
            }, {
              moduldCode: 7,
              moduleName: ‘三级 3-2-2‘,
            }]
          }]
        }],
      checkedkey: [],
      defaultProps: {
        children: "child",
        label: "moduleName",
        id:‘moduldCode‘ //可要可不要
      },
      // 取uniqueValue值的时候，列：uniqueValue[0]否则会是一个数组
      uniqueValue:‘‘//最后拿到的唯一选择的moduldCode值,相当于id
    }
  },

//节点选择状态发生改变时
    parentModules(data,checkbox,node){
      if(checkbox){
        // 后端返回的node-key不是id，是moduldCode
        let array = [data.moduldCode]
        this.$refs.tree.setCheckedKeys(array);
        this.uniqueValue =  this.$refs.tree.getCheckedKeys();
      }else{
        this.uniqueValue =  this.$refs.tree.getCheckedKeys();
        if(this.uniqueValue.length == 0){
          this.uniqueValue = ‘‘
        }
      }
    },

　　this.$axios.post("/admin/module/detail", {obj}).then(res => {
    　　this.checkedkey[0] = res.date.moduleCode; //树形权限回显
　　});
}