平行数据转换树形数据

let arr = [ { id: 3, name: "部门3", pid: 1 }, { id: 1, name: "部门1", pid: 0 }, { id: 5, name: "部门5", pid: 4 }, { id: 2, name: "部门2", pid: 1 }, { id: 4, name: "部门4", pid: "fff" } ]; function listToTree(arr) { const result = []; const map = new Map(); arr.forEach((item) => { map.set(item.id, item); }); for (let item of arr) { if (map.has(item.pid)) { map.get(item.pid).children ??= []; map.get(item.pid).children.push(item); } else { result.push(item); } } return result; }