I have a attendance model that has reference to the class model The response that is returned has two createdAt dates
const attendanceInfo = await Attendance.find({
student: studentId,
})
.populate('class', 'createdAt');
res.json({ data: attendanceInfo });
But for each object in attendanceInfo i want one additional field difference and its value will be createdAt(of class model) - createdAt(of attendance model)
EDIT:
The response i am getting at the moment is
{
_id: '614c6515a392d4a9dba59903',
class: {
_id: '614c5437a392d4a9dba59801',
createdAt: '2021-09-23T10:17:27.706Z',
},
createdAt: '2021-09-23T11:29:25.984Z',
updatedAt: '2021-09-23T11:29:25.984Z',
__v: 0,
},
And the result i am expecting is
{
_id: '614c6515a392d4a9dba59903',
difference: '01:11:58',
class: {
_id: '614c5437a392d4a9dba59801',
createdAt: '2021-09-23T10:17:27.706Z',
},
createdAt: '2021-09-23T11:29:25.984Z',
updatedAt: '2021-09-23T11:29:25.984Z',
__v: 0,
},
I am using moment.js
const attendanceInfo = [{
_id: '614c6515a392d4a9dba59903',
class: {
_id: '614c5437a392d4a9dba59801',
createdAt: '2021-09-23T10:17:27.706Z',
},
createdAt: '2021-09-23T11:29:25.984Z',
updatedAt: '2021-09-23T11:29:25.984Z',
__v: 0,
},{
_id: '614c6515a392d4a9dba59904',
class: {
_id: '614c5437a392d4a9dba59802',
createdAt: '2021-09-23T09:17:27.706Z',
},
createdAt: '2021-09-23T10:25:25.984Z',
updatedAt: '2021-09-23T10:25:25.984Z',
__v: 0,
}]
attendanceInfo.map((elem)=>{
let attendanceCreatedAt = moment(elem.createdAt);
let classCreatedAt = moment(elem.class.createdAt);
let differenceInsecs = attendanceCreatedAt.diff(classCreatedAt, 'seconds');
elem.difference = new Date(1000 * differenceInsecs).toISOString().substr(11, 8)
})
console.log(attendanceInfo)<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.2.1/moment.min.js"></script>