扁平化数组与树形结构的互转

[18888628835]

1.扁平化数组转树形结构

答案：

const data = [
  { id: 1, name: "部门1", pid: 0 },
  { id: 2, name: "部门2", pid: 1 },
  { id: 3, name: "部门3", pid: 1 },
  { id: 4, name: "部门4", pid: 3 },
  { id: 5, name: "部门5", pid: 4 },
  { id: 6, name: "部门5", pid: 0 },
  { id: 7, name: "部门5", pid: 6 },
  { id: 8, name: "部门5", pid: 9 },
  { id: 9, name: "部门5", pid: 7 }
];
/* 要求结果
      [
        {
          id: 1,
          name: "部门1",
          pid: 0,
          children: [
            {
              id: 2,
              name: "部门2",
              pid: 1,
              children: []
            },
            {
              id: 3,
              name: "部门3",
              pid: 1,
              children: [
                //  ,,,
              ]
            }
          ]
        }
      ];
*/
function arrayToTree(data) {
  let roots = [];
  let map = new Map();

  function setGroup(data) {
    for (let item of data) {
      if (item.pid === 0) {
        // roots中放置pid为0的根节点
        roots.push({ ...item, children: [] });
        continue;
      }
      // map将有pid的都按照pid分类，属性为pid，值为对应的children
      if (!map.has(item.pid)) {
        map.set(item.pid, []);
      }
      map.get(item.pid).push({ ...item, children: [] });
    }
  }
  setGroup(data);
  console.log(map);

  function setChildren(roots) {
    // 2.遍历根节点
    for (let root of roots) {
      // 3.匹配map的key（pid）与当前节点的id
      if (map.has(root.id)) {
        root.children = map.get(root.id);
      }
      // 4.如果当前节点有children，则将childen作为根节点，进入递归
      if (root.children.length > 0) {
        setChildren(root.children);
      }
    }
  }
  // 1.首先从roots根节点进入
  setChildren(roots);
  return roots;
}

let result = arrayToTree(data);
console.log(result);

2.树形结构转扁平化数组

      const data = [
        {
          id: 1,
          name: "部门1",
          pid: 0,
          children: [
            {
              id: 2,
              name: "部门2",
              pid: 1,
              children: []
            },
            {
              id: 3,
              name: "部门3",
              pid: 1,
              children: [
                {
                  id: 4,
                  name: "部门4",
                  pid: 3,
                  children: [
                    {
                      id: 5,
                      name: "部门5",
                      pid: 4,
                      children: []
                    }
                  ]
                }
              ]
            }
          ]
        }
      ];

      /* 要求结果
      [
        { id: 1, name: "部门1", pid: 0 },
        { id: 2, name: "部门2", pid: 1 },
        { id: 3, name: "部门3", pid: 1 },
        { id: 4, name: "部门4", pid: 3 },
        { id: 5, name: "部门5", pid: 4 }
      ];      
      */
function treeToFlat(data) {
  let root = [];
  for (let item of data) {
    let { children, ...rest } = item;
    root.push({ ...rest });
    if (item.children) {
      root = root.concat(treeToFlat(item.children));
    }
  }
  return root;
}
let result = treeToFlat(data);
console.log(result);