Javascript DateFormat for different timezones

Question

I'm a Java developer and I'm used to the SimpleDateFormat class that allows me to format any date to any format by settings a timezone.

Date date = new Date();

SimpleDateFormat sdf = new SimpleDateFormat("dd-MM-yyyy hh:mm:ss");

sdf.setTimeZone(TimeZone.getTimeZone("America/Los_Angeles"));
System.out.println(sdf.format(date)); // Prints date in Los Angeles

sdf.setTimeZone(TimeZone.getTimeZone("America/Chicago"));
System.out.println(sdf.format(date)); // Prints same date in Chicago

SimpleDateFormat is a pretty neat solution in Java but unfortunately I can't find any similar alternative in Javascript.

I'm extending the Date prototype in Javascript to do exactly the same. I have dates in Unix format but I want to format them in different timezones.

Date.prototype.format = function(format, timezone) {
    // Now what?
    return formattedDate;
}

I'm looking for a neat way to do this rather than a hack.

Thanks

Answer 1

There is a way to format for time zones.

console.log(new Date().toLocaleDateString('en-US', {timeZone: 'America/Denver'}))
// 11/13/2018
console.log(new Date().toLocaleTimeString('en-US', {timeZone: 'America/Denver'}))
// 2:30:54 PM
console.log(new Date().toLocaleTimeString('en-US', {timeZone: 'America/New_York'}))
// 4:31:26 PM

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toLocaleDateString

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toLocaleTimeString

Answer 2

The ISO Extended format for common date is YYYY-MM-DD, and for time is hh:mm:ss. Either format can be understood, unambiguously, worldwide.

See also: http://jibbering.com/faq/#dates