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Advent of Code Day Navigation Links

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

  1. // ==UserScript==
  2. // @name            Advent of Code Day Navigation Links
  3. // @namespace       Violentmonkey Scripts
  4. // @match           https://adventofcode.com/*/day/*
  5. // @grant           none
  6. // @version         1.0
  7. // @author          -
  8. // @description     This adds forward and backwards links to each day's page.
  9. // @author          josh
  10. // @namespace       https://gitlab.com/userscript4/advent-of-code-day-nav
  11. // @supportURL      https://gitlab.com/userscript4/advent-of-code-day-nav/-/issues
  12. // @license         MIT
  13. // ==/UserScript==
  14.  
  15. /**
  16.  * Return the url of the requested day.
  17.  * If less than 1 or greater than 25 provide a url to the overview page.
  18.  * @param {number} day
  19.  * @returns {string} A url to the requested day
  20.  */
  21. function makeURL(day) {
  22.     if (day < 1 || day > 25) {
  23.         return window.location.href.replace(/\/day\/.*/, '');
  24.     }
  25.     return window.location.href.replace(/(?<=\/day\/).*/, day);
  26. }
  27.  
  28. /**
  29.  * Create an anchor tag.
  30.  * @param {number} day 
  31.  * @param {string} text 
  32.  * @returns {HTMLAnchorElement}
  33.  */
  34. function makeAnchor(day, text) {
  35.     const anchor = document.createElement('a');
  36.     anchor.href = makeURL(day);
  37.     anchor.textContent = text;
  38.     return anchor
  39. }
  40.  
  41. /**
  42.  * Find the title, extract the day number, replace the `---` with links.
  43.  */
  44. function addNavigationLinks() {
  45.     const title = document.querySelector('article.day-desc > h2');
  46.     const currentDay = parseInt(title.textContent.match(/(?<=Day )[0-9]+(?=:)/)[0]);
  47.     title.textContent = title.textContent.match(/^--- (.*?) ---$/)[1];
  48.     title.prepend(makeAnchor(currentDay - 1, '<-- '));
  49.     title.append(makeAnchor(currentDay + 1, ' -->'));
  50. }
  51.  
  52. addNavigationLinks();