GitHub README tab render

Native github tab rendering and switching of README in multiple languages present in the project

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

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

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

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

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

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

(I already have a user script manager, let me install it!)

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.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name         GitHub README tab render
// @namespace    http://tampermonkey.net/
// @version      1.1.0
// @description  Native github tab rendering and switching of README in multiple languages present in the project
// @author       Longlone & Gemini
// @license      MIT
// @match        https://github.com/*/*
// @icon         https://github.githubassets.com/pinned-octocat.svg
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    if (!document.getElementById('custom-readme-tab-styles')) {
        const style = document.createElement('style');
        style.id = 'custom-readme-tab-styles';
        style.innerHTML = `
            nav[aria-label="Repository files"] {
                min-width: 0 !important;
            }
            nav[aria-label="Repository files"] ul {
                flex-wrap: nowrap !important;
                overflow-x: auto !important;
                overflow-y: hidden !important;
                scrollbar-width: none !important;
            }
            nav[aria-label="Repository files"] ul::-webkit-scrollbar {
                display: none !important;
            }
            nav[aria-label="Repository files"] ul li {
                flex-shrink: 0 !important;
            }
            nav[aria-label="Repository files"] ul a[aria-current="page"]::after,
            nav[aria-label="Repository files"] ul a[aria-selected="true"]::after {
                bottom: 0 !important;
                transform: translateX(50%) !important;
            }
        `;
        document.head.appendChild(style);
    }

    const globalCache = {
        repoPath: '',
        files: [],
        defaultHTML: null,
        langs: {}
    };

    function getRepoInfo() {
        const parts = window.location.pathname.split('/').filter(Boolean);
        if (parts.length >= 2) return { owner: parts[0], repo: parts[1] };
        return null;
    }

    function scanLinks(repoInfo) {
        const links = Array.from(document.querySelectorAll('a[href]'));
        const seen = new Set();
        const results = [];
        const regex = new RegExp(`^/${repoInfo.owner}/${repoInfo.repo}/blob/[^/]+/readme.*\\.md$`, 'i');

        links.forEach(a => {
            const href = a.getAttribute('href') || '';
            if (regex.test(href)) {
                const name = href.split('/').pop();
                if (!seen.has(name.toLowerCase()) && name.toLowerCase() !== 'readme.md') {
                    seen.add(name.toLowerCase());
                    results.push({ name: name, url: href });
                }
            }
        });
        return results;
    }

    async function fetchAndRender(lang, url, targetTab) {
        let article = document.querySelector('article.markdown-body');

        if (!article) {
            const navUl = document.querySelector('nav[aria-label="Repository files"] ul');
            if (!navUl) {
                window.location.href = url;
                return;
            }
            // 找到原生的 README 标签
            const nativeTabLink = Array.from(navUl.querySelectorAll('a')).find(a => {
                const span = a.querySelector('span[data-component="text"]');
                return span && span.textContent.trim().toUpperCase() === 'README' && !a.classList.contains('custom-readme-tab-link');
            });

            if (nativeTabLink) {
                // 模拟点击切回原生 README,触发 GitHub 的 PJAX/React 路由
                nativeTabLink.click();

                // 轮询等待 Markdown 容器被 GitHub 渲染出来
                let retry = 0;
                const timer = setInterval(() => {
                    if (document.querySelector('article.markdown-body') || retry > 50) { // 最多等 5 秒
                        clearInterval(timer);

                        // 重新获取 DOM 节点(防止被 React 销毁)
                        const newTargetTab = document.querySelector(`.custom-readme-tab-link[data-lang="${lang}"]`) || targetTab;
                        if (document.querySelector('article.markdown-body')) {
                            // 容器就绪,重新执行渲染逻辑
                            fetchAndRender(lang, url, newTargetTab);
                        } else {
                            window.location.href = url; // 超时保底
                        }
                    }
                    retry++;
                }, 100);
                return;
            } else {
                window.location.href = url; // 保底跳转
                return;
            }
        }

        const allTabs = document.querySelectorAll('nav[aria-label="Repository files"] ul a');
        allTabs.forEach(a => a.removeAttribute('aria-current'));
        targetTab.setAttribute('aria-current', 'page');

        targetTab.scrollIntoView({ behavior: 'smooth', block: 'nearest', inline: 'center' });

        if (globalCache.langs[lang]) {
            article.innerHTML = globalCache.langs[lang];
            return;
        }

        const currentHTML = article.innerHTML;
        article.innerHTML = `
            <div style="text-align:center; padding: 80px 20px; color: var(--color-fg-muted);">
                <svg style="animation: rotate 2s linear infinite; margin-bottom: 12px; fill: currentColor;" aria-hidden="true" height="32" viewBox="0 0 16 16" width="32" class="octicon octicon-sync">
                    <path d="M1.705 8.005a.75.75 0 0 1 .834.656 5.5 5.5 0 0 0 9.592 2.97l-1.204-1.204a.25.25 0 0 1 .177-.427h3.646a.25.25 0 0 1 .25.25v3.646a.25.25 0 0 1-.427.177l-1.38-1.38A7.002 7.002 0 0 1 1.05 8.84a.75.75 0 0 1 .656-.834ZM8 2.5a5.487 5.487 0 0 0-4.131 1.869l1.204 1.204A.25.25 0 0 1 4.896 6H1.25A.25.25 0 0 1 1 5.75V2.104a.25.25 0 0 1 .427-.177l1.38 1.38A7.002 7.002 0 0 1 14.95 7.16a.75.75 0 0 1-1.49.178A5.5 5.5 0 0 0 8 2.5Z"></path>
                </svg>
                <style>@keyframes rotate { 100% { transform: rotate(360deg); } }</style>
                <br><span style="font-weight: 500;">Loading ...</span>
            </div>`;

        try {
            const res = await fetch(url);
            const text = await res.text();
            const doc = new DOMParser().parseFromString(text, 'text/html');
            const newMarkdown = doc.querySelector('article.markdown-body');

            if (newMarkdown) {
                article.innerHTML = newMarkdown.innerHTML;
                globalCache.langs[lang] = newMarkdown.innerHTML;
            } else throw new Error("README parse error");
        } catch(err) {
            article.innerHTML = currentHTML;
            alert(`Loading ${lang} Error, please check network`);
        }
    }

    function restoreDefault(nativeTab) {
        const article = document.querySelector('article.markdown-body');
        if (!article) return;

        const allTabs = document.querySelectorAll('nav[aria-label="Repository files"] ul a');
        allTabs.forEach(a => a.removeAttribute('aria-current'));
        nativeTab.setAttribute('aria-current', 'page');

        nativeTab.scrollIntoView({ behavior: 'smooth', block: 'nearest', inline: 'center' });

        if (globalCache.defaultHTML) {
            article.innerHTML = globalCache.defaultHTML;
        } else {
            window.location.reload();
        }
    }

    if (!window._readmeTabsDelegated) {
        document.addEventListener('click', (e) => {
            const customTab = e.target.closest('.custom-readme-tab-link');
            if (customTab) {
                e.preventDefault();
                e.stopPropagation();
                fetchAndRender(customTab.dataset.lang, customTab.dataset.url, customTab);
                return;
            }

            const nativeLink = e.target.closest('a');
            if (nativeLink) {
                const nav = nativeLink.closest('nav[aria-label="Repository files"]');
                if (nav && !nativeLink.classList.contains('custom-readme-tab-link')) {
                    const span = nativeLink.querySelector('span[data-component="text"]');
                    const activeCustom = document.querySelector('.custom-readme-tab-link[aria-current="page"]');

                    if (span && span.textContent.trim().toUpperCase() === 'README') {
                        if (activeCustom) {
                            e.preventDefault();
                            e.stopPropagation();
                            restoreDefault(nativeLink);
                        }
                    } else {
                        if (activeCustom) {
                            activeCustom.removeAttribute('aria-current');
                        }
                    }
                }
            }
        }, true);
        window._readmeTabsDelegated = true;
    }

    const observer = new MutationObserver(() => {
        const repoInfo = getRepoInfo();
        if (!repoInfo) return;

        const currentPath = `${repoInfo.owner}/${repoInfo.repo}`;
        if (globalCache.repoPath !== currentPath) {
            globalCache.repoPath = currentPath;
            globalCache.files = [];
            globalCache.defaultHTML = null;
            globalCache.langs = {};
        }

        if (globalCache.files.length === 0) {
            globalCache.files = scanLinks(repoInfo);
        }

        if (globalCache.files.length === 0) return;

        const navUl = document.querySelector('nav[aria-label="Repository files"] ul');
        if (!navUl) return;

        const nativeTabLink = Array.from(navUl.querySelectorAll('a')).find(a => {
            const span = a.querySelector('span[data-component="text"]');
            return span && span.textContent.trim().toUpperCase() === 'README' && !a.classList.contains('custom-readme-tab-link');
        });

        if (!nativeTabLink) return;
        const nativeTabLi = nativeTabLink.closest('li');

        if (nativeTabLink.hasAttribute('aria-current')) {
            const article = document.querySelector('article.markdown-body');
            if (article && !globalCache.defaultHTML) {
                globalCache.defaultHTML = article.innerHTML;
            }
        }

        let insertRef = nativeTabLi;
        globalCache.files.forEach(file => {
            let lbl = file.name.replace(/^readme[-_.]?/i, '').replace(/\.md$/i, '').toUpperCase() || file.name;

            const existing = document.querySelector(`.custom-readme-tab-link[data-lang="${lbl}"]`);
            if (!existing) {
                const li = document.createElement('li');
                li.className = 'prc-UnderlineNav-UnderlineNavItem-syRjR custom-readme-li';

                const a = document.createElement('a');
                a.href = '#';
                a.className = 'prc-components-UnderlineItem-7fP-n custom-readme-tab-link';
                a.dataset.lang = lbl;
                a.dataset.url = file.url;

                a.innerHTML = `
                    <span data-component="icon">
                        <svg data-component="Octicon" aria-hidden="true" focusable="false" class="octicon octicon-book" viewBox="0 0 16 16" width="16" height="16" fill="currentColor" display="inline-block" overflow="visible" style="vertical-align: text-bottom;">
                            <path d="M0 1.75A.75.75 0 0 1 .75 1h4.253c1.227 0 2.317.59 3 1.501A3.743 3.743 0 0 1 11.006 1h4.245a.75.75 0 0 1 .75.75v10.5a.75.75 0 0 1-.75.75h-4.507a2.25 2.25 0 0 0-1.591.659l-.622.621a.75.75 0 0 1-1.06 0l-.622-.621A2.25 2.25 0 0 0 5.258 13H.75a.75.75 0 0 1-.75-.75Zm7.251 10.324.004-5.073-.002-2.253A2.25 2.25 0 0 0 5.003 2.5H1.5v9h3.757a3.75 3.75 0 0 1 1.994.574ZM8.755 4.75l-.004 7.322a3.752 3.752 0 0 1 1.992-.572H14.5v-9h-3.495a2.25 2.25 0 0 0-2.25 2.25Z"></path>
                        </svg>
                    </span>
                    <span data-component="text" data-content="${lbl}">${lbl}</span>
                `;
                li.appendChild(a);

                insertRef.after(li);
                insertRef = li;
            }
        });
    });

    observer.observe(document.body, { childList: true, subtree: true });

})();