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@burglekitt/gmt

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Temporal-based date and time utilities with timezone support and polyfill integration

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import { Temporal } from "@js-temporal/polyfill"; import { rfc3339DateTime } from "../../regex/index.js"; /** * Parse a strict RFC 3339 datetime string into a zoned ISO 8601 datetime * string. * * - Accepts `T`, `t`, or a single space as the date/time separator (all * three are valid RFC 3339, unlike GMT's own zoned strings which always * use `T`) and either `Z`/`z` or a numeric `±HH:MM` offset. * - RFC 3339 carries no IANA zone name, so the parsed offset becomes the * result's time zone identifier too (e.g. `Z` → `+00:00[+00:00]`) — the * same fixed-offset-as-zone convention `parseRfc2822` uses. * - Rejects GMT's own bracketed zoned strings (`...+00:00[UTC]`) — that * annotation is not valid RFC 3339 input; use `Temporal.ZonedDateTime.from` * / `isValidZonedDateTime` directly for GMT's native format instead. * * @param value RFC 3339 datetime string (e.g. "2024-03-15T14:30:00-04:00") * @returns zoned ISO 8601 datetime string, or "" on invalid input * * @example parseRfc3339("2024-03-15T14:30:00-04:00") // "2024-03-15T14:30:00-04:00[-04:00]" * @example parseRfc3339("2024-03-15T14:30:00Z") // "2024-03-15T14:30:00+00:00[+00:00]" * @example parseRfc3339("2024-03-15T14:30:00+00:00[UTC]") // "" (bracket annotation not valid RFC 3339) * @example parseRfc3339("not a date") // "" */ export function parseRfc3339(value) { if (typeof value !== "string") return ""; const match = rfc3339DateTime.exec(value); if (match === null) return ""; const [, year, month, day, hour, minute, second, fraction, offsetToken] = match; const offset = offsetToken === "Z" || offsetToken === "z" ? "+00:00" : offsetToken; const isoDateTime = `${year}-${month}-${day}T${hour}:${minute}:${second}${fraction ?? ""}`; try { return Temporal.PlainDateTime.from(isoDateTime) .toZonedDateTime(offset) .toString(); } catch { return ""; } }