weekOfYearForDate

Signature

weekOfYearForDate(value: string): number

import { weekOfYearForDate } from "@northguild/gmt/plain/calculate";

Return the ISO week number for a given ISO 8601 date string.

• Uses Temporal.PlainDate.weekOfYear (Monday-based ISO weeks).
• Returns null for invalid input.

Parameters

Parameter	Type	Description
value	string	ISO 8601 date string

Returns

Week number (1-53) or null on invalid input

Examples

weekOfYearForDate("2024-01-01") // 1
weekOfYearForDate("2024-01-07") // 1
weekOfYearForDate("2024-01-08") // 2
weekOfYearForDate("2024-12-31") // 1
weekOfYearForDate("invalid") // null

Source

plain/calculate/weekOfYearForDate.ts