无限极评论笔记

data：[{"id":1675755921416,"pid":1675755866738,"uid":1,"username":"zhangsan","comment":"新年好"},{"id":1675755895321,"pid":1675755866738,"uid":2,"username":"lisi","comment":"大家都好"},{"id":1675755880977,"pid":0,"uid":2,"username":"lisi","comment":"李四动态"},{"id":1675755866738,"pid":1675755806728,"uid":3,"username":"wangwu","comment":"张总好呀"},{"id":1675755849801,"pid":1675755806728,"uid":2,"username":"lisi","comment":"你好"},{"id":1675755806728,"pid":0,"uid":1,"username":"zhangsan","comment":"张三发表动态"}]

列表结构转树形结构：

formatTree(data) {
    const result = [];
    const map = {};

    data.forEach((item) => {
      map[item.id] = item;
    });

    data.forEach((item) => {
      const parent = map[item.pid];

      if (parent) {
        (parent.children || (parent.children = [])).unshift(item);
      } else {
        result.unshift(item);
      }
    });

    return result;
  }

思路：
1、先把数组转列表结构，根据id来存每一项
map:{id1：item, id2：item}

2、循环data数组 ，根据item的pid去读取map的值即：map[item.pid]， 存在说明有父级，把该item放到map[tem.pid].children，不存在，放到result，最后返回