37 lines
1.0 KiB
TypeScript
37 lines
1.0 KiB
TypeScript
export function isValidTimeZone(tz: string): boolean {
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try {
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new Intl.DateTimeFormat("en", { timeZone: tz });
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return true;
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} catch {
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return false;
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}
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}
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export function formatLocalIsoWithOffset(now: Date, timeZone?: string): string {
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const explicit = timeZone ?? process.env.TZ;
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const tz =
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explicit && isValidTimeZone(explicit)
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? explicit
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: Intl.DateTimeFormat().resolvedOptions().timeZone;
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const fmt = new Intl.DateTimeFormat("en", {
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timeZone: tz,
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year: "numeric",
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month: "2-digit",
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day: "2-digit",
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hour: "2-digit",
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minute: "2-digit",
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second: "2-digit",
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hour12: false,
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fractionalSecondDigits: 3 as 1 | 2 | 3,
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timeZoneName: "longOffset",
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});
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const parts = Object.fromEntries(fmt.formatToParts(now).map((p) => [p.type, p.value]));
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const offsetRaw = parts.timeZoneName ?? "GMT";
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const offset = offsetRaw === "GMT" ? "+00:00" : offsetRaw.slice(3);
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return `${parts.year}-${parts.month}-${parts.day}T${parts.hour}:${parts.minute}:${parts.second}.${parts.fractionalSecond}${offset}`;
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}
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