扁平数组转成树形数据

    { 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: 1 },
    { id: 5, name: '部门5', pid: 2 },
    { id: 6, name: '部门6', pid: 3 },
    { id: 7, name: '部门7', pid: 4 },
]

function arrayToTree(list) {
    let result = [];
    let map = {};
    for (let item of list) {
        map[item.id] = { ...item, children: [] };
        if (item.pid === 0) {
            let newMap = map[item.id];
            result.push(newMap);
        } else {
            map[item.pid].children.push(map[item.id]);
        }
    }
    return result;
}
console.log(arrayToTree(arr));