fs模块循环加异步，最后在外部拼接，如何读取到想要的值？

[刘杰强]

学习VUE时，自己写了个node，都是用的JSON文件假数据,遇到需要将几个文件中的数组拼接一下，然后再传出去，一直困扰于fs模块的异步问题，循环取值后在循环体中可以取到，但是在外部因为异步原因，直接跳过了循环，直接将空数组传了出去，不知如何在循环体外部获取这个拼接起来的数组

// 获取购物车列表
app.get('/getshopcarlist/', function (req, res) {
    //这里传过来一串  ，分隔的数字
    var id = req.query.ID
    var idlist = id.split(",")
    var pagePersonmessage = []

    function getFileBylist(path,succCb,errCb){
        fs.readFile(path, function (err, data) {
            if (err) {
                return errCb(err)
            } else {
                // console.log(path)
                var person = data.toString();
                person = JSON.parse(person);
                var pagePerson = person.message[0]
                // console.log(pagePersonmessage)
                succCb(pagePerson)
            }
        })
    }

    for (let i in idlist) {
        var path = "./shopcarlist/shopcarlist" + idlist[i] + ".json"
        getFileBylist(path,
            function(data){
                pagePersonmessage = pagePersonmessage.concat(data)
                console.log(pagePersonmessage + 'hahaha')
        },
        function(err){
            console.log('失败的结果，使用失败回调' + err.message)
        })
         
    }

    
    res.header("Access-Control-Allow-Origin", "*");
    res.header("Access-Control-Allow-Headers", "X-Requested-With,Origin,Content-Type,Accept");
    res.header("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS");

    console.log(pagePersonmessage);     
    // var pagePersonList = { "status": 0, "message": pagePersonmessage }
    res.send();
    res.end();


});

[scscms太阳光]

async await 去了解下

[刘杰强]

// 获取购物车列表
app.get('/getshopcarlist/', function (req, res) {
//这里传过来一串 ，分隔的数字
var id = req.query.ID
var idlist = id.split(",")
var pagePersonmessage = []

function getFileBylist(path) {
return new Promise(function (resolve, reject) {
fs.readFile(path, function (err, data) {
if (err) {
return reject(err)
} else {
console.log(path+"----path")
var person = data.toString();
person = JSON.parse(person);
var pagePerson = person.message[0]
// console.log(pagePersonmessage)
resolve(pagePerson)
}
})
})
}

var time = async function () {
var arr = [];
for (let i in idlist) {
var path = "./shopcarlist/shopcarlist" + idlist[i] + ".json"
arr=await getFileBylist(path)
pagePersonmessage=pagePersonmessage.concat(arr)
}
// console.log(pagePersonmessage)
res.header("Access-Control-Allow-Origin", "*");
res.header("Access-Control-Allow-Headers", "X-Requested-With,Origin,Content-Type,Accept");
res.header("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS");

// console.log(pagePersonmessage);
var pagePersonList = { "status": 0, "message": pagePersonmessage }
res.send(pagePersonList);
res.end();
}


time()

});