How to get Date according to my timezone with specific format

Question

I need to format the JavaScript Date object. It should display Israel date, in the format: yyyy/mm/dd.

I tried this -

const locale = 'he-IL';
const dateOptions =  {timeZone:'Asia/Jerusalem',year: 'numeric', month: '2-digit', day: '2-digit'};
console.log( new Date(record.value).toLocaleDateString(locale, dateOptions) )

I'm getting from local computer -

=> 2020-06-22

And from a server - hosted on Amazon Cloud :

=> 06/22/2020

I tried with another locales, but the result is different - probably according to the server locale.

Answer 1

ECMAScript date objects are just a time value, an offset in milliseconds from 1970-01-01T00:00:00Z with a range of about ±285,000 years, making them effectively UTC.

The time value is calculated when the date instance is created based on the value passed to the constructor. If no value is passed, the current time value is calculated based on the system clock and timezone settings. That is the only data value that a Date object has. All other data values of a date instance are calculated from the time value (e.g. getMonth, getHours, toString, etc., including their UTC equivalents) or retrieved from the system (such as getTimezoneOffset).

So you can't specify a date's timezone because it doesn't have one. The current system timezone settings are used when using non–UTC methods, otherwise they're ignored too.

If you want to get a timestamp for a particular place, such as Israel, you can set the system settings to a suitable location and use non–UTC methods. Alternatively, you can use the timeZone option of an Intl.DateTimeFormat instance to generate some appropriate values using formatToParts, then format them as required.

The only tricky part is getting the values from the array returned by formatToParts, e.g. the following uses reduce to create a parts object that is more convenient to use when formatting:

let parts = new Intl.DateTimeFormat('en', {
                year: 'numeric',
                month: '2-digit',
                day: '2-digit',
                timeZone:'Asia/Jerusalem'})
              .formatToParts(new Date())
              .reduce((acc, part) => {
                acc[part.type] = part.value;
                return acc;
              }, Object.create(null));
              
let timeStamp = `${parts.year}/${parts.month}/${parts.day}`;

console.log(timeStamp);

An alternative is to select a language that has the parts in the order you want, then replace the separator. It's somewhat more risky as different implementations may have a different idea about the format related to a particular language or dialect such as order of parts and leading zeros, e.g.

console.log(
  new Date().toLocaleDateString('he-IL', {timeZone:'Asia/Jerusalem'}).replace(/\D/g,'/')
);
console.log(
  new Date().toLocaleDateString('en-CA', {timeZone:'Asia/Jerusalem'}).replace(/\D/g,'/')
);