date-fns-tz
Version:
Time zone support for date-fns v3 with the Intl API
36 lines (35 loc) • 1.39 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.tzIntlTimeZoneName = void 0;
/**
* Returns the formatted time zone name of the provided `timeZone` or the current
* system time zone if omitted, accounting for DST according to the UTC value of
* the date.
*/
function tzIntlTimeZoneName(length, date, options) {
const dtf = getDTF(length, options.timeZone, options.locale);
return 'formatToParts' in dtf ? partsTimeZone(dtf, date) : hackyTimeZone(dtf, date);
}
exports.tzIntlTimeZoneName = tzIntlTimeZoneName;
function partsTimeZone(dtf, date) {
const formatted = dtf.formatToParts(date);
for (let i = formatted.length - 1; i >= 0; --i) {
if (formatted[i].type === 'timeZoneName') {
return formatted[i].value;
}
}
return undefined;
}
function hackyTimeZone(dtf, date) {
const formatted = dtf.format(date).replace(/\u200E/g, '');
const tzNameMatch = / [\w-+ ]+$/.exec(formatted);
return tzNameMatch ? tzNameMatch[0].substr(1) : '';
}
// If a locale has been provided `en-US` is used as a fallback in case it is an
// invalid locale, otherwise the locale is left undefined to use the system locale.
function getDTF(length, timeZone, locale) {
return new Intl.DateTimeFormat(locale ? [locale.code, 'en-US'] : undefined, {
timeZone: timeZone,
timeZoneName: length,
});
}