How to add objects to this array?

Question

I have created a get route for a page which displays user info. In this I have created a list array which I have passed to render object and this list contains 2 things one is user image which is displaying correctly and the other is his attendance in form of an array which includes different objects.

The problem is when I am pushing this objects they are not getting added to the dates array and are not getting displayed in the list array. Also when I am console logging the objects they are getting displayed individually.

router.get("/me", ensureAuthenticated, async (req, res) => {
    var empCode = req.user.empCode;
    var list = []
    list.photo = await Document.findOne({
        empCode: empCode
    }).then(employee => {
        return employee.photo;
    });


    list.attendance = await Attendance.findOne({
        empCode: empCode
    }).then(employee => {    
        var dates = [];    
        var emp = {};
        employee.years.forEach(year => {
            yearName = year.name;
            emp["year"] = yearName;
            year.months.forEach(month => {
                monthName = month.name;
                emp["month"] = monthName;
                month.days.forEach(day => {
                    date = day.date;
                    inTime = day.inTime;
                    outTime = day.outTime;
                    status = day.status;
                    emp["date"] = date;
                    emp["inTime"] = inTime;
                    emp["outTime"] = outTime;
                    emp["status"] = status;
                    dates.push(emp); // Here is i console log the objects are getting displayed.
                });                
            });            
        });
        return dates;
    });

    console.log(list);
    res.render("me", {
        user: req.user,
        list
    });
});

If I console.log(emp); in forEach loop this is the result.

{
  year: '2020',
  month: 'Jan',
  date: '1',
  inTime: '09:40',
  outTime: '18:10',
  status: 'On Time'
}
{
  year: '2020',
  month: 'Feb',
  date: '3',
  inTime: '10:15',
  outTime: '18:15',
  status: 'Late'
}
{
  year: '2020',
  month: 'Feb',
  date: '4',
  inTime: '10:20',
  outTime: '18:20',
  status: 'Late'
}
[ photo: '', attendance: [] ]

But if I do dates.push(emp); then I get.

[
  photo: '',
  attendance: [
    {
      year: '2020',
      month: 'Feb',
      date: '4',
      inTime: '10:20',
      outTime: '18:20',
      status: 'Late'
    },
    {
      year: '2020',
      month: 'Feb',
      date: '4',
      inTime: '10:20',
      outTime: '18:20',
      status: 'Late'
    },
    {
      year: '2020',
      month: 'Feb',
      date: '4',
      inTime: '10:20',
      outTime: '18:20',
      status: 'Late'
    }
  ]
]

And what I want is this.

[
  photo: '',
  attendance: [
    {
  year: '2020',
  month: 'Jan',
  date: '1',
  inTime: '09:40',
  outTime: '18:10',
  status: 'On Time'
}
{
  year: '2020',
  month: 'Feb',
  date: '3',
  inTime: '10:15',
  outTime: '18:15',
  status: 'Late'
}
{
  year: '2020',
  month: 'Feb',
  date: '4',
  inTime: '10:20',
  outTime: '18:20',
  status: 'Late'
}
  ]
]

this code should display 3 objects in attendance array but instead it displays last object 3 times. — Deepank Mehta
– Deepank Mehta, Commented Feb 5, 2020 at 5:42
Could you copy and paste your expected output and your current output into your original post? Also to clarify, you're saying you're getting the correct output when you log emp while in the forEach loop? — Sherman Hui
– Sherman Hui, Commented Feb 5, 2020 at 5:43
please check i have updated the question with the results i am getting and what is want — Deepank Mehta
– Deepank Mehta, Commented Feb 5, 2020 at 6:06

Qonvex620 · Accepted Answer · 2020-02-05 06:23:04Z

2

You should convert your variable emp to a new instance of object. you should push to array like this.

dates.push(JSON.parse(JSON.stringify(emp));

This will convert your variable emp into a new instance of object without any connection to the object you were accessing during your iteration.

Variables that are assigned a non-primitive value are given a reference to that value. That reference points to the object’s location in memory. The variables don’t actually contain the value.

Primitives vs. References Please read this docs to understand further value vs reference

edited Feb 5, 2020 at 6:23

answered Feb 5, 2020 at 6:11

Qonvex620

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1 Comment

Deepank Mehta Over a year ago

hi i am stuck after this step too can you please help this is the post. stackoverflow.com/questions/60073924/…

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