Check if event is in future - Yup validation - reactjs

Question

I'm currenlty working on yup validation for a page in project. I'm stuck on the following:
User chooses date, timezone and specific time of the event (he can choose times from 00:00 to 23:45 every fifteen minutes). Now, I need to validate if chosen time is in the future. I am really confused: should I first convert current moment to users chosen timezone, or convert user's moment to local timezone, or something else.
Here's what I did first when I was careless about the timezone:
[keys.startTime]: yup
.number()
.required(errors.required)
.when(['date'], (date, schema: any) => {
const currentTimeInMinutes = moment().hours() * 60 + moment().minutes()
if (
moment(date).date() === moment().date() &&
moment(date).month() === moment().month() &&
moment(date).year() === moment().year()
)
return schema.min(currentTimeInMinutes, errors.pastTime)
}),
But then I realised that I didn't take into account chosen timezone.
Start time here represents number of minutes from 00:00 to chosen time, for example if user chooses 00:15, startTime will be 15.
Thanks in advance.

Answer 1

You need to compare - the current time (at the point of submission) with the user's selected/entered date and startTime both in the user's selected zone.
// Calculate the offset of the timezone that user selected from UTC
const utcOffset = '+05:30'; // Example of a time zone in India
const currentTime = moment().utcOffset(utcOffset);
const userSelectionTime =
moment(date).utcOffset(utcOffset)
.startOf('day')
.add(startTime, 'minutes');
/*
* Check if the difference between the `userSelectionTime` and the `currentTime`
* is greater than 0 minutes (you can change this as per your requirements)
*/
const selectionIsValid = userSelectionTime.diff(currentTime, 'minutes') > 0;