How to convert from GMT/UTC to local time and back using momentjs?

Question

I have the following string:

\"December 25, 2018 01:02:20\"

I intend this to be GMT/UTC Using moment.js, how do I convert this to local time and back to UTC?

Answer 1

Since your input represent UTC time, you have to use moment.utc (as suggested by others in the comments):

By default, moment parses and displays in local time.

If you want to parse or display a moment in UTC, you can use moment.utc() instead of moment().

Moreover, since your input string is not in a format recognized by moment(String) (ISO 8601 or RFC 2822), you have to pass format parameter as second argument of moment.utc, see String + Format parsing section of the docs.

Here a code sample:

var input = "December 25, 2018 01:02:20";
var fmt = 'MMMM DD, YYYY HH:mm:ss';
var m = moment.utc(input, fmt);
console.log(m.local().format(fmt));
console.log(m.utc().format(fmt));