TypeError：无法读取 null 的属性“userID”

Posted 2023-02-23

【中文标题】TypeError：无法读取 null 的属性“userID”

【英文标题】：TypeError: Cannot read property 'userID' of null

【发布时间】：2019-04-06 00:30:23

【问题描述】：

错误：

TypeError: 无法读取属性 'userID' of null

列出了我的UserDB.js 和profileController.js，不确定这个错误是关于什么的。当我从我的页面转换并转到 myItems(cart) 时，它会吐出这个错误。

router.get('/myItems', function(req, res, next)
res.locals.signin = req.session.signin;
var UserDB = require('../models/UserDB');
var Users = UserDB.getUser();
console.log(Users);
var LocalUser = Users.find(function (ele) if (ele.userID === req.session.signin) return ele;);
if (SessionOn) 
    var UserProfiles = UserDB.GetUserProfiles();
    var LocalProfile = UserProfiles.find(function (ele) if (ele.GetUserID() === LocalUser.userID) return ele;);


res.render('myItems', LocalUser: LocalUser, LocalProfile: LocalProfile, Session: res.locals.signin, SessionOn: SessionOn);
next()
);

-------

var mongoose = require('mongoose');
   mongoose.connect('mongodb://localhost:27017/DB');
   var Schema = mongoose.Schema;

    var userDataSchema = new Schema(
    userID: type: String, required: true,
    password: type: String, required: true,
    firstName: type: String, required: true,
    lastName: type: String, required: true,
    email: type: String, required: true,
    city: type: String, required: true,
    state: type: String, required: true,
    zipCode: type: String, required: true

    ,collection: 'User');

    var UserData = mongoose.model('User', userDataSchema);

    function getAllUsers()
    try
        return UserData.find();
     catch(e)
        console.log(e);
    
    

    function getUser(user)
    try
        return  UserData.findOne(userID: user);

    catch(e)
        console.log("error " + e);
    
    

    module.exports.getUser = getUser;
    module.exports.getAllUsers = getAllUsers;

【参考方案1】：

您的猫鼬模型查询函数 Users.find() 为您提供了一个对象数组 因此，如果您想以您使用的方式访问它 试试这样

Users.findOne(userid:xxx,callback);

如果使用 find() 方法，则必须访问数组索引

Users.find(userId:xxx,(users)=>users[0]==neededId