Is it possible to parse strings from local string?

[Wernfried]

When I run DateTime.now().toLocaleString(DateTime.DATE_SHORT) then luxon return local string as '17.3.2025'. Is it possible to do it the other way around?

DateTime.fromFormatExplain('17.3.2025', DateTime.DATE_SHORT)

DateTime.fromFormat('17.3.2025', DateTime.DATE_SHORT)

do not work. Or maybe is there any possibility to get dd.MM.yyyy out from DateTime.DATE_SHORT?

[Wernfried]

Maybe a prototype of such function would be this one:

function localeFormat(format) {
   const formatLookup = {
      year: { numeric: 'yyyy' },
      month: { numeric: 'M', '2-digit': 'MM', short: 'MMM', long: 'MMMM' },
      day: { numeric: 'dd' },
      hour: { numeric: 'HH' },
      minute: { numeric: 'mm' },
      second: { numeric: 'ss' },
      millisecond: { numeric: 'SSS' }
   };

   const locale = DateTime.now().toLocaleParts(format);
   const ret = [];
   for (let token of locale) {
      if (token.type == 'literal') {
         ret.push(token.value);
      } else if (['year', 'month', 'day', 'hour', 'minute', 'second', 'millisecond'].includes) {
         ret.push(formatLookup[token.type][format[token.type]]);
      } else {
         ret.push('N/A');
      }
   }
   return ret.join('');
}

console.log(DateTime.now().toLocaleString(DateTime.DATE_FULL)); => 18. März 2025
console.log(localeFormat(DateTime.DATE_FULL)); => dd. MMMM yyyy


DateTime.fromFormat('18. März 2025', 'dd. MMMM yyyy', {locale: DateTime.now().locale}); 
=> DateTime { ts: 2025-03-18T00:00:00.000+01:00, zone: Europe/Zurich, locale: de-CH }

I would assume tokens 'year', 'month', 'day', 'hour', 'minute', 'second', 'millisecond' are sufficient. Other tokens are not required and some of them would not be possible, anyway.

[dobon]

Fortunately there IS a way to generate the format code for a provided or else current locale:

>DateTime.parseFormatForOpts(DateTime.DATE_SHORT);
>> "M/d/yyyyy"
>DateTime.parseFormatForOpts(DateTime.DATE_SHORT, {locale: 'de-ch'});
>> "d.M.yyyyy"

You can use this code with DateTime.fromFormat to accomplish your goal.