获取树形数据

<template lang="html">
  <div class=""></div>
</template>

<script>
export default {
  data() {
    return {
      list: [
        {
          _id: "5debbbe8bdc6bc2150ab6ddc",
          pid: 0,
          title: "技术团队"
        },
        {
          _id: "5debbc69f22ee22d0861eb29",
          pid: "5debbbe8bdc6bc2150ab6ddc",
          title: "移动开发"
        },
        {
          _id: "5debbc81f22ee22d0861eb2a",
          pid: "5debbbe8bdc6bc2150ab6ddc",
          title: "网站开发"
        },
        {
          _id: "5debbc8af22ee22d0861eb2b",
          pid: "5debbbe8bdc6bc2150ab6ddc",
          title: "销售部门"
        },
        {
          _id: "5debbc94f22ee22d0861eb2c",
          pid: 0,
          title: "关于我们"
        },
        {
          _id: "5debbca2f22ee22d0861eb2d",
          pid: 0,
          title: "数码"
        },
        {
          _id: "5debbcb7f22ee22d0861eb2e",
          pid: "5debbca2f22ee22d0861eb2d",
          title: "笔记本电脑"
        },
        {
          _id: "5dec6ae9aac8f231246afa84",
          pid: "5debbc69f22ee22d0861eb29",
          title: "前端开发"
        }
      ]
    };
  },
  created() {
    console.log(JSON.stringify(this.getTree1(this.list), null, 2));
  },
  methods: {
    getTree1(docs) {
      let obj = {};
      docs.map(item => {
        obj[item._id] = item;
      });
      let arr = [];
      docs.map(item => {
        let parent = obj[item.pid];
        if (parent) {
          (parent.children || (parent.children = [])).push(item);
        } else {
          arr.push(item);
        }
      });
      return arr;
    },
    // 递归
    getTree2(docs) {
      let arr = [];
      docs.map(item => {
        let tempArr = docs.filter(childItem => childItem.pid === item._id);
        if (tempArr.length) {
          this.getTree(tempArr);
          item.children = tempArr;
        }
        if (!item.pid) {
          arr.push(item);
        }
      });
      return arr;
    }
  }
};
</script>