@lonu/stc
Version:
A tool for converting OpenApi/Swagger/Apifox into code.
42 lines (41 loc) • 1.31 kB
JavaScript
// Copyright 2018-2025 the Deno authors. MIT license.
// This module is browser compatible.
import { DAY, WEEK } from "./constants.js";
const DAYS_PER_WEEK = 7;
const Day = {
Sun: 0,
Mon: 1,
Tue: 2,
Wed: 3,
Thu: 4,
Fri: 5,
Sat: 6,
};
/**
* Returns the ISO week number of the provided date (1-53).
*
* @param date Date to get the week number of.
* @returns The week number of the provided date.
*
* @example Basic usage
* ```ts
* import { weekOfYear } from "@std/datetime/week-of-year";
* import { assertEquals } from "@std/assert";
*
* assertEquals(weekOfYear(new Date("2020-12-28T03:24:00")), 53);
*
* assertEquals(weekOfYear(new Date("2020-07-10T03:24:00")), 28);
* ```
*/
export function weekOfYear(date) {
const workingDate = new Date(Date.UTC(date.getFullYear(), date.getMonth(), date.getDate()));
const day = workingDate.getUTCDay();
const nearestThursday = workingDate.getUTCDate() +
Day.Thu -
(day === Day.Sun ? DAYS_PER_WEEK : day);
workingDate.setUTCDate(nearestThursday);
// Get first day of year
const yearStart = new Date(Date.UTC(workingDate.getUTCFullYear(), 0, 1));
// return the calculated full weeks to nearest Thursday
return Math.ceil((workingDate.getTime() - yearStart.getTime() + DAY) / WEEK);
}