推送方法不起作用，它只显示空数组

Question

我通过在数组中推送错误消息来动态添加错误，但是当我在函数中调用它时它不执行任何操作。

router.post('/Registration',function(req,res){
var path = '/auth/Registration';
req.assert('username', 'Username is required').notEmpty();
req.assert('email', 'valid email required').notEmpty().isEmail();
req.assert('password', 'password is required').notEmpty();
req.assert('cpassword', 'password is required').notEmpty();
req.assert('phoneNumber', 'phone Number is required').isNumeric();
req.assert('age', 'age is required').notEmpty().isInt();
req.assert('designation', 'designation is required').notEmpty().isInt();
req.assert('timing', 'timing is required').notEmpty().notEmpty().isInt();
req.assert('sex', 'sex is required').notEmpty();
req.assert('joiningDate', 'joiningDate is required').notEmpty();
var errors = req.validationErrors();
if(errors) {
    req.session.error = errors;
    return  res.redirect('/auth/Registration');
}
var errorsArr = [];
User.findOne({"username":req.body.username},function(err,user){
    if(user){
        errorsArr.push({"msg":"Username already been taken."});
    }
    User.findOne({"email":req.body.email},function(err1,user1){
        if(user1) {
            errorsArr.push({"msg":"Email already been taken."});
        }
        if(errorsArr.length > 0)
        {
            req.session.error = errorsArr;
            return  res.redirect('/auth/Registration');
        }

    });

});
var newUser = new User();
newUser.username = req.body.username;
newUser.password = req.body.password;
newUser.sex = req.body.sex;
newUser.email = req.body.email;
newUser.phoneNumber = req.body.phoneNumber;
newUser.age = req.body.age;
newUser.designation = req.body.designation;
newUser.timing = req.body.timing;
var CurrentDate = moment.tz(new Date(req.body.joiningDate),"Asia/Karachi").unix();
newUser.joiningDate = CurrentDate;
newUser.save(function(err,user){
    if(!err)
        return res.redirect('/auth/Login');
});
});

当我控制台 errorArray 时，它会显示一个空数组。

Answer 1

findOne 函数似乎正在执行一些数据库查询。我假设。如果是这样，那么它返回一个 Promise 并且你不能那样处理它。 试试这个

User.findOne({"username":req.body.username}).then(function(user){
   if(user){
      errorsArr.push({"msg":"Username already been taken."});
   }
}, function(err){

})

Answer 2

您可以通过使用 promise $q 或简单地嵌套或回调来解决此问题。

简单的嵌套代码：

var errorsArr = [];
User.findOne({"username":req.body.username},function(err,user){
    // you should check err
    if(user){
        errorsArr.push({"msg":"Username already been taken."});
    }

    User.findOne({"email":req.body.email},function(err1,user1){
        // you should check err1
        if(user1) {
            errorsArr.push({"msg":"Email already been taken."});
        }

        console.log(errorsArr);

        if(errorsArr.length > 0)
        {
           req.session.error = errorsArr;
           return  res.redirect('/auth/Registration');
        }

    });

});