JavaScript Dates

I fully expected the 'use moment.js' part at the end. Javascript dates are certainly unpleasant, but moment can be kind of a blunt instrument at times.

There's growing support behind Luxon, a sub-project of moment that may eve become a full replacement. I've found it quite refreshing.

There's also date-fns which is designed with tree shaking in mind and people seem to enjoy it.

Or if you're a Java native, JS-Joda emulates the same API as the java.time libraries in Java 8.

Also +1 for GMT != UTC.