Toogle beta version

Extension for foodsharing.de - toggles to beta version and back
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// ==UserScript==
// @name        Toogle beta version
// @namespace   Violentmonkey Scripts
// @match       https://*.foodsharing.*/*
// @run-at      document-idle
// @version     1.3
// @author      Martin G. (166111)
// @license     MIT
// @require     https://cdn.jsdelivr.net/npm/@violentmonkey/shortcut@1
// @description Extension for foodsharing.de - toggles to beta version and back
// ==/UserScript==

function isBeta() {
    return window.location.hostname.startsWith("beta.");
}

function initButton() {
    if (document.getElementById("fs-toggle-beta-btn")) return;

    // Try prod container first, then common header targets on beta, or fall back to body
    const targetContainer = 
        document.querySelector(".metanav-container") || 
        document.querySelector("header nav") || 
        document.querySelector("#nav") ||
        document.body;

    if (!targetContainer) return;

    const btn = document.createElement("button");
    btn.id = "fs-toggle-beta-btn";
    btn.innerHTML = isBeta() ? "prod" : "beta";

    // Basic styling so it remains visible if appended to body/header
    btn.style.marginLeft = "8px";
    btn.style.cursor = "pointer";

    btn.onclick = () => {
        const aktuelleURL = window.location.href;
        const betaMuster = /(\bhttps?:\/\/)(www\.)?/;
        let neueURL;

        if (isBeta()) {
            neueURL = aktuelleURL.replace("beta.", "");
        } else {
            neueURL = aktuelleURL.replace(betaMuster, "$1beta.");
        }

        window.location.href = neueURL;
    };

    targetContainer.appendChild(btn);
}

// Run initial attempt
initButton();

// Observe DOM changes in case Vue re-renders the navigation
const observer = new MutationObserver(() => {
    if (!document.getElementById("fs-toggle-beta-btn")) {
        initButton();
    }
});
observer.observe(document.body, { childList: true, subtree: true });