User script to normalize LilyPond URL versions

userscript.js

// ==UserScript==
// @name         Normalize LilyPond URL version
// @namespace    http://tampermonkey.net/
// @version      2025-12-21
// @description  Change the version number in LilyPond documentation URLs to a fixed version.
// @author       Lucas Werkmeister
// @match        https://lilypond.org/doc/v*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=lilypond.org
// @grant        GM_xmlhttpRequest
// @connect      lilypond.org
// ==/UserScript==

(async function() {
    'use strict';

    const url = new URL(document.location);
    let [_, doc, version, ...rest] = url.pathname.split('/');
    if (version === 'v2.24') {
        return;
    }
    version = 'v2.24';
    url.pathname = [_, doc, version, ...rest].join('/');
    const response = await new Promise((resolve, reject) => GM_xmlhttpRequest({
        method: 'HEAD',
        url,
        onload: resolve,
        onerror: reject,
        onabort: reject,
        ontimeout: reject,
    }));
    if (response.status === 200) {
        document.location = url;
    }
})();