element-ui动态级联选择器回显问题详解(二十多行代码搞定）

[
    {
    	id:1, level:0,pid:0,name:'测试1'            
    },
    {
    	id:2, level:0,pid:0,name:'测试2'            
    },
    {
    	id:11, level:1,pid:1,name:'测试1-1'            
    },
    {
    	id:12, level:2,pid:11,name:'测试1-1-1'            
    }
]

<el-cascader :props="categoryProps" 
            v-model="cascaderData"></el-cascader>

      cascaderData: '12',
      categoryProps: {
        emitPath: false,
        label:'name', // 字段必须统一
        value:'id', // 字段必须统一
        lazy: true,
        lazyLoad (node, resolve) {
          const { level,value } = node;
          console.log(value);
          let nodes = [];
          if (level == 0) { // 第一级
            nodes = catalogueList.filter(v=>{return v.level == 0});
          }else { // 后面两级
            nodes = catalogueList.filter(v=>{return v.pid == value});
          };

          resolve(nodes.map(v=>({
            id: v.id,
            name: v.name,
            leaf: level >= 2
          })));
        }
      }, // 级联选择器显示数据

    setLazyLoad(node, resolve) {
      const { level,value } = node;
      const cascaderData = this.cascaderData;
      // 第一级数据
      let nodes = [];

      nodes = catalogueList.filter(v=>{return v.level == 0});
      // 选中的第三级某位数据
      const threeFind = catalogueList.find(v=>{return v.id == cascaderData});
      if (value) {
        // 查询数据
        const unknownFind = catalogueList.find(v=>v.id == value);

        if (level == 1) {
          let twoData = catalogueList.filter(v=>v.pid == unknownFind.id);
          nodes = twoData; // 第二级
        }else if (level == 2) {
          let threeData = catalogueList.filter(v=>v.pid == unknownFind.id);
          nodes = threeData.map(v=>{return {id:v.id,name:v.name,level:v.level,leaf:true}}); // 第三级
        };
      }else {
        // 选中的第二级某位数据
        let twoFind = catalogueList.find(v=>v.id == threeFind.pid);
        // 第三级数据
        let threeData = catalogueList.filter(v=>v.pid == twoFind.id);
        // 选中的第一级某位数据
        const oneFind = catalogueList.find(v=>{return v.id == twoFind.pid});
        // 第二级数据
        let twoData = catalogueList.filter(v=>{return v.pid == oneFind.id});
        // nodes = nodes.map(v=>{return {id:v.id,name:v.name,level:v.level}}); // 第一级
        const oneIndex = nodes.findIndex(v=>{return v.id == oneFind.id});
  
        nodes[oneIndex].children = twoData; // 第二级
  
        const twoIndex = nodes[oneIndex].children.findIndex(v=>v.id == twoFind.id);
        nodes[oneIndex].children[twoIndex].children = threeData.map(v=>{ // 第三季
          return {
            id:v.id,
            name:v.name,
            level:v.level,
            leaf: true,
          }
        });
      }

      resolve(nodes);
    },