luxon convert local time to utc given a timezone

Since you know the timezone of you input date, you can use the zone option when parsing it. As fromISO docs states:

public static fromISO(text: string, opts: Object): DateTime

opts.zone: use this zone if no offset is specified in the input string itself.

Then you can use toUTC to convert your DateTime to UTC:

"Set" the DateTime's zone to UTC. Returns a newly-constructed DateTime.

Equivalent to setZone('utc')

Here a live sample:

const DateTime = luxon.DateTime;
const d = DateTime.fromISO('2019-07-09T18:45', {zone: 'America/Chicago'});
console.log(d.toISO());
console.log(d.toUTC().toISO());

<script src="https://cdn.jsdelivr.net/npm/[email protected]/build/global/luxon.js"></script>

You can refer the following luxon function:

1. isInDST https://moment.github.io/luxon/docs/class/src/datetime.js~DateTime.html#instance-get-isInDST

To check whether current time is based on DST or not!

2. toUTC : function to convert to UTC based time

https://moment.github.io/luxon/docs/class/src/datetime.js~DateTime.html#instance-method-toUTC