JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://momentjs.com/downloads/moment.js"></script>
<script src="http://momentjs.com/downloads/moment-timezone-with-data-2010-2020.js"></script>

JavaScript

function awayFromHomeTZ(tz) {
    var there = moment.tz(tz);
    var here = moment();
    var thereHHMM = there.hour() * 60 + there.minute();
    var hereHHMM = here.hour() * 60 + here.minute();
    return Math.abs(thereHHMM - hereHHMM) > 59;
}

var tests = ["America/Halifax", "America/New_York", "America/Chicago", "America/Denver", "America/Vancouver", "America/Anchorage"]; 

var yourIn = null;
    
for(var i = 0; i < tests.length; i++) {
    if(!awayFromHomeTZ(tests[i])) {
        if(yourIn == null) {
            yourIn = tests[i];
        } else {
            alert("Test failed: " + yourIn + " " + tests[i]);
            
        }
    }
}
if(yourIn == null) {
    alert("You are not in an American time zone");
} else {
    alert("You are in " + yourIn);
}