tree转list

tree转list:

treeToList(datas){
            var arr = [];
            formateData(datas,0);
            function formateData(datas,level){
                var level = level || 0;
                level ++;
                for(var i in datas){
                    arr.push({id:datas[i]['id'],orgNodeName:datas[i]['名字'],name:datas[i]['name'],level:level,value:datas[i]['value'],});
                    if(datas[i].children){
                        formateData(datas[i].children,level);
                    }
                }
            }
            return arr;
        },

list转tree：

例:
test() {
 const list = [
        { id: 1, name: 'a' },
        { id: 11, name: 'aa', pid: 1 },
        { id: 12, name: 'aaa', pid: 1 },
        { id: 13, name: 'aaaa', pid: 1 },
        { id: 2, name: 'b' },
        { id: 22, name: 'bb', pid: 2 },
        { id: 23, name: 'bbb', pid: 2 },
        { id: 24, name: 'bbbb', pid: 2 },
        { id: 3, name: 'c' },
        { id: 31, name: 'cc', pid: 3 },
        { id: 32, name: 'ccc', pid: 3 },
        { id: 33, name: 'cccc', pid: 3 },
        { id: 111, name: 'a11', pid: 11 },
        { id: 112, name: 'aa11', pid: 11 },
        { id: 1121, name: 'aa112', pid: 112 }
      ];
      //prev 是我们最终要生成的树型机构
      //curr 为当前的数据
      //i为索引
      //arr为我们整个list
      const result = list.reduce(function (prev, curr, i, arr) {
          curr.children = arr.filter((v) => v.pid === curr.id);
          if (!curr.pid) {
              prev.push(curr);
          }
          return prev;
      }, []);
      console.log('list', list);
      console.log('tree', result);
      },