Find used dateformat (d/m/Y..." and timeformat in JS

I am trying to find the time zone, the date format (d.m.Y, Y/m/d,...) and the time format (H:i, h:i A,...).

I get the time zone with Intl.DateTimeFormat().resolvedOptions().timeZone... But how do I get the other data?

I pass the data to PHP with an XMLHttpRequest and want to specify the date and time format there afterwards.

Solution

There is no way to get the date format in your desired output because it's not standardized, but you can use formatToParts() to get the value split up in the different parts:

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const parts = new Intl.DateTimeFormat(undefined,
  { dateStyle: 'short', timeStyle: 'short' }
).formatToParts();
console.log(parts);

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From this you can transform it into your desired format. You may need to change the dateStyle or timeStyle options.

Alternative

However, as pointed out in the comments, I would recommend not to deal with time zones and date formats on backend or database side, but rather work there with ISO date strings. To format a date, you can use the format function:

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const myDate = new Date('2023-03-31T09:31:47.362Z');
const intlDateTimeFormat = new Intl.DateTimeFormat(undefined,
  { dateStyle: 'short', timeStyle: 'short' });
const formattedDate = intlDateTimeFormat.format(myDate);
console.log(formattedDate);

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