Advent of Code Day Navigation Links

This adds forward and backwards links to each day's page.

K instalaci tototo skriptu si budete muset nainstalovat rozšíření jako Tampermonkey, Greasemonkey nebo Violentmonkey.

You will need to install an extension such as Tampermonkey to install this script.

K instalaci tohoto skriptu si budete muset nainstalovat rozšíření jako Tampermonkey nebo Violentmonkey.

K instalaci tohoto skriptu si budete muset nainstalovat rozšíření jako Tampermonkey nebo Userscripts.

You will need to install an extension such as Tampermonkey to install this script.

K instalaci tohoto skriptu si budete muset nainstalovat manažer uživatelských skriptů.

(Už mám manažer uživatelských skriptů, nechte mě ho nainstalovat!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(Už mám manažer uživatelských stylů, nechte mě ho nainstalovat!)

// ==UserScript==
// @name            Advent of Code Day Navigation Links
// @namespace       Violentmonkey Scripts
// @match           https://adventofcode.com/*/day/*
// @grant           none
// @version         1.0
// @author          -
// @description     This adds forward and backwards links to each day's page.
// @author          josh
// @namespace       https://gitlab.com/userscript4/advent-of-code-day-nav
// @supportURL      https://gitlab.com/userscript4/advent-of-code-day-nav/-/issues
// @license         MIT
// ==/UserScript==

/**
 * Return the url of the requested day.
 * If less than 1 or greater than 25 provide a url to the overview page.
 * @param {number} day
 * @returns {string} A url to the requested day
 */
function makeURL(day) {
    if (day < 1 || day > 25) {
        return window.location.href.replace(/\/day\/.*/, '');
    }
    return window.location.href.replace(/(?<=\/day\/).*/, day);
}

/**
 * Create an anchor tag.
 * @param {number} day 
 * @param {string} text 
 * @returns {HTMLAnchorElement}
 */
function makeAnchor(day, text) {
    const anchor = document.createElement('a');
    anchor.href = makeURL(day);
    anchor.textContent = text;
    return anchor
}

/**
 * Find the title, extract the day number, replace the `---` with links.
 */
function addNavigationLinks() {
    const title = document.querySelector('article.day-desc > h2');
    const currentDay = parseInt(title.textContent.match(/(?<=Day )[0-9]+(?=:)/)[0]);
    title.textContent = title.textContent.match(/^--- (.*?) ---$/)[1];
    title.prepend(makeAnchor(currentDay - 1, '<-- '));
    title.append(makeAnchor(currentDay + 1, ' -->'));
}

addNavigationLinks();