year

const year: RegExp = /^(?:\d{4}|\+\d{6}|-(?!0{6})\d{6})$/;

RegExp matching the shape of an ISO 8601 year: 4 digits, or a sign and 6 digits (Temporal’s DateYear).

Examples

import { year } from "@northguild/gmt";

year.test("2024") // true
year.test("+275760") // true (expanded year)
year.test("-271821") // true (negative expanded year)
year.test("+999999") // true (shape only; outside Temporal's range)
year.test("-000000") // false (negative zero)
year.test("24") // false (too few digits)
year.test("20245") // false (5 digits without a sign)

Source

regex/date.ts