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Library for getting dates in the weeks around another date
Ce script ne devrait pas être installé directement. C'est une librairie créée pour d'autres scripts. Elle doit être inclus avec la commande // @require https://update.greasyfork.org/scripts/559387/1718432/getRelativeWeekday.js
// ==UserScript==
// @name getRelativeWeekday
// @namespace https://github.com/nate-kean/
// @version 2025.12.21
// @description Library for getting dates in the weeks around another date
// @author Nate Kean
// @icon data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==
// @grant none
// @license MIT
// ==/UserScript==
// @ts-check
const Day = Object.freeze({
SUNDAY: 0,
MONDAY: 1,
TUESDAY: 2,
WEDNESDAY: 3,
THURSDAY: 4,
FRIDAY: 5,
SATURDAY: 6,
});
/**
* @typedef {typeof Day[keyof typeof Day]} DayT
*/
/**
* NEXT: The next occurrence (always in the future)
* LAST: The last occurrence (always in the past)
* THIS: The nearest occurrence in the current week (Mon-Sun)
*/
const DateDir = Object.freeze({
LAST: -1,
THIS: 0,
NEXT: 1,
});
/**
* @typedef {typeof DateDir[keyof typeof DateDir]} DateDirT
*/
/**
* Get a relative weekday from a target date.
*
* By Claude Sonnet 4.5:
* https://claude.ai/public/artifacts/d666c5fe-6e91-4186-a46f-ae4eb046636e
*
* Manually ported to JavaScript because I was using this for a Python project
* before
*
* @param {Date} targetDate Date to calculate from
* @param {DayT} weekday
* @param {DateDirT} direction
* @param {boolean} includeToday whether to include targetDate if it matches weekday
* @returns {Date}
*
* @example
* // returns Sun Jan 12 2025 00:00:00
* const target = new Date("01/15/2025"); // Wednesday
* getRelativeWeekday(target, DateDir.LAST, Day.SUNDAY);
* @example
* // returns Thu Jan 16 2025 00:00:00
* getRelativeWeekday(target, DateDir.THIS, Day.THURSDAY);
* @example
* // returns Thu Jan 23 2025 00:00:00
* getRelativeWeekday(target, DateDir.NEXT, Day.THURSDAY);
*/
function getRelativeWeekday(
targetDate,
direction,
weekday,
includeToday = false,
) {
const currentWeekday = targetDate.getDay();
const result = new Date(targetDate);
switch (direction) {
case DateDir.LAST: {
// Calculate days back to the target weekday
let daysForward = (currentWeekday - weekday) % 7; // Zero or negative
if (daysForward === 0 && !includeToday) {
// If this would make the result land on today, make it a week
// ago instead
daysForward = 7;
}
result.setDate(result.getDate() + daysForward);
return result;
}
case DateDir.THIS: {
// Find the date within the current week (Monday to Sunday)
// Current week starts on the Monday of targetDate's week
let daysForward = weekday - currentWeekday; // Zero or positive
if (daysForward === 0 && !includeToday) {
// If this would make the result land on today, make it a week
// from now instead
daysForward = 7;
}
result.setDate(result.getDate() + daysForward);
return result;
}
case DateDir.NEXT: {
// Calculate days forward to the target weekday
let daysForward = (weekday - currentWeekday) % 7; // Zero or positive
daysForward += 7;
result.setDate(result.getDate() + daysForward);
return result;
}
}
}