let getTree = function (data, pid) {
    let result = []
    let temp
    for (let i = 0; i < data.length; i++) {
        if (data[i].pid == pid) {
            temp = getTree(data, data[i].id)
            if (temp.length > 0) {
                data[i].children = temp
            }
            result.push(data[i])
        }
    }
    return result
}

let result = getTree(data, req.body.pid)
let result = getTree(data, req.body.page_id)