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Format Dates and Times in Lichess4545

Format's the dates and times in the Lichess4545 Lonewolf league's website to use the user's timezone and preferences. Might work with other Lichess4545 webpages, but I'm to lazy to check.

// ==UserScript==
// @name         Format Dates and Times in Lichess4545
// @namespace    http://tampermonkey.net/
// @version      2025-08-11
// @description  Format's the dates and times in the Lichess4545 Lonewolf league's website to use the user's timezone and preferences. Might work with other Lichess4545 webpages, but I'm to lazy to check.
// @author       Charles Moxey
// @match        https://www.lichess4545.com/lonewolf/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=lichess4545.com
// @require      https://cdn.jsdelivr.net/npm/[email protected]/build/global/luxon.min.js
// @license MIT
// @grant        none
// ==/UserScript==

const DateTime = luxon.DateTime;

// "Borrowed" from user "funky-future" on Stack Overflow (https://stackoverflow.com/a/50537862/16080090)
function replaceInText(element, pattern, replacement) {
    for (let node of element.childNodes) {
        switch (node.nodeType) {
        case Node.ELEMENT_NODE:
            replaceInText(node, pattern, replacement);
            break;
        case Node.TEXT_NODE:
            node.textContent = node.textContent.replace(pattern, replacement);
            break;
        case Node.DOCUMENT_NODE:
            replaceInText(node, pattern, replacement);
        }
    }
}

function formatDateTime(isoDateTime) {
    let dt = DateTime.fromISO(isoDateTime).setLocale('en-US');

    const today = DateTime.now();

    let time_str = dt.toLocaleString(DateTime.TIME_SIMPLE);
    let date_str;

    let daysAwayFromToday = dt.startOf('day').diff(today.startOf('day'), 'days').days

    if (-3 <= daysAwayFromToday && daysAwayFromToday <= -2)
        date_str = `${Math.abs(daysAwayFromToday)} days ago @ `
    else if (daysAwayFromToday === -1)
        date_str = 'Yesterday @ '
    else if (daysAwayFromToday === 0)
        date_str = 'Today @ ';
    else if (daysAwayFromToday === 1)
        date_str = 'Tomorrow @ ';
    else
        date_str = dt.toFormat('EEE MMM d @ ');

    console.log(daysAwayFromToday)

    return date_str + time_str
}

(function() {
    'use strict';

    let timeTags = document.querySelectorAll('time');
    timeTags.forEach( (tag) => {
        let formattedDateTime = formatDateTime(tag.getAttribute('datetime'))
        console.log(formattedDateTime)
        tag.innerHTML = formattedDateTime

        replaceInText(tag.parentElement, /UTC/, DateTime.local().offsetNameShort)
    }
    )
}
)();