Mongoose or MongoDB removing 24 hours from date? - mongodb

Question

I have to be doing something wrong but I cannot figure out what it is. I currently have a date field in my application that has a value format of MMMM, D YYYY.
For this example, I am going to be using the date October 1, 2018.
In the application, the user selects October 1, 2018 which logs as
October 1, 2018
Later I convert this date into a savable date by using var docDate = new Date($('#insuranceExpiration').val()).toISOString(); which logs as
2018-10-01T04:00:00.000Z
I then add this to an object stringify it and send it to the server where I log the date and shows as
2018-10-01T04:00:00.000Z
I then use Mongoose to save this date to MongoDB but when I go to see the saved date I show
2018-09-30T04:00:00.000Z
I cannot figure out for the life of me why I am seeing a date 24 hours in the past from the date I choose. Below is the mongoose code to see if I am doing something wrong on that end.
app.post('/api/myDocuments/insuranceGeneral', function(req, res ) {
console.log(req.body.expires);
// prints 2018-10-01T04:00:00.000Z
InsuranceGeneral.findOneAndUpdate({
_id: req.rsaConPortal.id
}, {
$set: {
"documents.insurance.name": req.body.name,
"documents.insurance.expires": req.body.expires,
"documents.insurance.url": req.body.url,
"documents.insurance.uploadDate": req.body.uploadDate
}
}, function(err, doc) {
if (err) throw err;
res.send('Success');
});
});
Even if I use a standard javascript date object I can print this on the browswer log
Mon Oct 01 2018 00:00:00 GMT-0400 (Eastern Daylight Time)
This prints on the sever just before mongoose
2018-10-01T04:00:00.000Z
But this is the end result in mongodb
2018-09-30T04:00:00.000Z

Answer 1

I think you and your server in different timezone. And mongodb uses GMT. If you are not declaring time in your iso date, it is setting it's time as 00:00.000Z. So for GMT this is one day earlier. Simply you should convert your date to GMT, you can use moment or you can fix problem by subtraction offset from date like this:
var offset = new Date().getTimezoneOffset() * 60000;
var date = new Date(new Date($('#insuranceExpiration').val())) - offset).toISOString();
or with moment.js
var date = moment($('#insuranceExpiration').val()).tz('GMT').format('YYYY-MM-DD');