I know this seems like a straight forward question - but although Moment.js and moment timezone are very powerful tools for getting/setting and formatting dates..
I'm having an issue snapping my application to a single timezone.
What I want, is for a user to choose from a date/time picker - and to send that as a unix timestamp in UTC.. but the date/time picker MUST be considered to be BST.
In other words, even if you're using the site from abroad - the date/time you select should be the UTC value for if you had chosen it in the UK.
var local = moment(dateTime).unix();
var london = moment(dateTime).tz('Europe/London').unix();
var berlin = moment(dateTime).tz('Europe/Berlin').unix();
Assuming dateTime is an ISO8601 string, and you want the date to be in the Europe/London timezone at all times all you need is:
This tells moment to interpret that time as London time, provided that it does not have a specified offset. If it has an offset, it is going to convert from the time of the offset to London time.
So, for me in America/Chicago, you can see the effect of this:
//unix timestap in london time moment.tz('2016-12-30', 'Europe/London').unix() 1483056000 //parse that timestamp back to my local time moment.unix(1483056000).format() "2016-12-29T18:00:00-06:00"
Keep in mind that London has multiple offsets due to Daylight Saving Time. I think this is what you want.
If you wanted it to always keep a fixed offset of +0, then you could just use UTC: