如何使用 async 和 foreach 遍历数组

Question

我正在尝试创建一个 api，它将在 expressjs 中创建一个包含成员的组。到目前为止它是这样工作的：

使用 req.body 中的 JSON 对象发出 post 请求，我将使用它创建一个新组。如果 req.body 对象的 members 数组包含成员 id，将其添加到组成员数组，否则创建一个新用户，然后将其 id 添加到数组。

基本上只是添加一个现有用户，新用户将被创建然后添加。为此，我需要遍历 req.body 中的成员数组并检查一个对象。

但是下面的代码似乎不能正常工作。我得到 console.log(group_info.members); 的奇怪结果。我希望它在数组中包含 id 的对象，但会得到随机结果。 foreach 循环中似乎有问题。请帮我解决一下。

var express = require('express');
var router = express.Router();
var Group = require('../models/GroupModel');
var User = require('../models/UserModel');
var async = require("async");

router.post('/', function (req, res, next) {
var group_members = [];
var group_info = req.body;

//see if a member object is sent, create user for that else just add the user id to group_members array

async.forEach(group_info.members, function (member, callback) {
    if (typeof member == "object") {
        //create new user and add the _id to members array
        var user = new User(member);
        user.save(function (err) {
            if (err) return res.status(500).send(err);
            var member_object = {id: user._id};
            group_members.push(member_object);
        }).then(callback);
    } else {
        var member_object = {id: member };
        group_members.push(member_object);
        callback();
    }
}, function (err) {
    //final call back
    group_info.members = group_members; //replace the original array in request body with the new array of users
    console.log(group_info.members);
    var group = new Group(group_info);
    group.save(function (err) {
        if (err) return res.status(500).send(err);
        res.json(group);
    });
});
});

Answer 1

var group_members = [];
var group_info = req.body;

var todo = group_info.members.length;
var done = 0;
if(todo == 0)
{
    return saveGroup(res, group_members);
}
else
{
    group_info.members.forEach(function (member, index, array) {
       if (typeof member == "object") {
            //create new user and add the _id to members array
            var user = new User(member);
            user.save(function (err, savedObject) {
                if (err || !savedObject)
                {
                    return res.status(500).send(err);
                }
                else
                {

                    var member_object = {id: savedObject._id};
                    group_members.push(member_object);
                    if(++done >= todo)
                    {
                        return saveGroup(res, group_info, group_members);
                    }
                }
            });
        } else {
           var member_object = {id: member };
           group_members.push(member_object);
           if(++done >= todo)
           {
                return saveGroup(res, group_info, group_members);
            }
        }
    });
}

function saveGroup(res, group_info, group_members)
{
    group_info.members = group_members; //replace the original array in request body with the new array of users
    console.log(group_info.members);
    var group = new Group(group_info);
    group.save(function (err) {
        if (err) return res.status(500).send(err);
        res.json(group);
    });
}

Answer 2

看起来你弄错了它的 eachSeries 不是 forEach，所以只需替换 :

 async.forEach(group_info.members, function (member, callback)

与：

async.eachSeries(group_info.members, function (member, callback)

更新

正如评论中指出的 forEach 是 async each API 的别名，你可以阅读文档 here，谢谢@megawac 指出这一点。

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