temporal.ts

// Run with:
// $ TZ="Europe/London" deno run --unstable-temporal

const DATE_FORMAT: Intl.DateTimeFormatOptions = {
    month: 'long',
    year: 'numeric',
    day: 'numeric',
    hour: '2-digit',
    hour12: false,
    minute: '2-digit',
    second: '2-digit',
};

let date = Temporal.Now.zonedDateTimeISO(Temporal.TimeZone.from('Asia/Bangkok'));

const formatter = new Intl.DateTimeFormat(undefined, {
    ...DATE_FORMAT,
    timeZone: date.timeZone // <- Le sigh
});

console.log(formatter.format(date));