方法一：按層級(jí)遍歷

function treeOptionsFromQueryResult1(data, id, pid, rootPid) { 
//data:源數(shù)據(jù),id:元素id,pid:父元素id;rootPid:根節(jié)點(diǎn)id
  const parentChildrenMap = {}; //首先構(gòu)造所有父子關(guān)系的對(duì)象，即每一層數(shù)據(jù)與下級(jí)數(shù)據(jù)對(duì)應(yīng)關(guān)系
  each(data, (row) => {
    if (parentChildrenMap[row[pid]] === undefined) {
      parentChildrenMap[row[pid] = [];
    }
    parentChildrenMap[row[pid].push({
      id: row[id],
      children: [],
      name: row.name,
    });
  });
  let q = [];
  q.push(parentChildrenMap[rootPid][0]);//可以理解為children元素，首次push根節(jié)點(diǎn)
  while (q.length > 0) { //判斷如果p長(zhǎng)度大于0執(zhí)行邏輯，與下面每次shift刪除首元素構(gòu)成遍歷
    const curNode = q.shift();//取到當(dāng)前節(jié)點(diǎn)就是q里面的首節(jié)點(diǎn)，并在q里面刪除
    curNode.children = parentChildrenMap[curNode.id];//根據(jù)之前父子對(duì)應(yīng)關(guān)系給當(dāng)前節(jié)點(diǎn)賦予children子元素集合
    q = union(q, curNode.children); //union為lodash庫(kù)里面的方法，遍歷children元素，為每一項(xiàng)賦它的子元素集合
  }
  return parentChildrenMap[rootPid];//返回對(duì)象里面的根節(jié)點(diǎn)對(duì)應(yīng)的值
}

方法二：

function getTreeData(data, id, pid, children, rootPid) {
  const cloneData = JSON.parse(JSON.stringify(data));
  return cloneData.filter((father) => {
    const childrenArr = cloneData.filter(child => father[id] === child[pid]);
    father[children] = childrenArr.length > 0 ? childrenArr : '';
    return father[pid] === rootPid;
  });
}