I am using moment js to convert user system time to user specified time zone as per his preference. User system time zone is IST and he is specifing a different time zone. For setting the same I am using
moment.tz.setDefault("Pacific/Pago_Pago");
But in one of the scenario I am getting different dates. If I do
moment().startOf('day')
I am getting today's date as Thu Oct 28 2021 00:00:00 GMT+0530 (India Standard Time), But if I am doing
moment(endDate).startOf('day')
I am getting Thu Oct 27 2021 00:00:00 GMT+0530 (India Standard Time) Where end date is the result of last statement i.e. Thu Oct 28 2021 00:00:00 GMT+0530 (India Standard Time)
What I am doing wrong here.
The timezone used when a moment object is created stays as part of the object and is used for subsequent processing. The effect described will happen if the default timezone is changed after the initial moment object is created.
E.g.
// Set default to IST (+5:30)
moment.tz.setDefault('Asia/Kolkata');
// Create initial moment using default timezone
let start = moment().startOf('day');
// Changing the default here doesn't affect above moment
moment.tz.setDefault('Pacific/Pago_Pago');
// This still uses the initial +5:30 offset, not -11:00 for Pago Pago
let timestamp = start.toString();
// This uses the timestamp for the original timezone, but
// then gets start of day in new default timezone
let end = moment(timestamp).startOf('day');
console.log( `Start: ${start.toString()}\nEnd : ${end.toString()}` );<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.9.0/moment-with-locales.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment-timezone/0.5.31/moment-timezone-with-data-10-year-range.js"></script>