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Cursor Rule Markdown Renderer for GitHub

Renders Cursor Rules (*.mdc) markdown on GitHub into actual Markdown locally, using the marked library + highlight.js.

目前為 2025-05-28 提交的版本，檢視 最新版本。

  1. // ==UserScript==
  2. // @name         Cursor Rule Markdown Renderer for GitHub
  3. // @namespace    https://github.com/texarkanine
  4. // @version      2025-05-27
  5. // @description  Renders Cursor Rules (*.mdc) markdown on GitHub into actual Markdown locally, using the marked library + highlight.js.
  6. // @author       Texarkanine
  7. // @match        https://github.com/*
  8. // @icon         data:image/png;base64,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
  9. // @grant        GM_addStyle
  10. // @require      https://cdnjs.cloudflare.com/ajax/libs/marked/15.0.7/marked.min.js
  11. // @require      https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.11.1/highlight.min.js
  12. // ==/UserScript==
  13.  
  14. (function() {
  15. 	'use strict';
  16.  
  17. 	const DEBUG = true;
  18.  
  19. 	const MDC_FILE_REGEX = /^https:\/\/github\.com\/.*\.mdc$/;
  20. 	const YAML_FRONTMATTER_REGEX = /^---\s*\n([\s\S]*?)\n---\s*\n([\s\S]*)$/;
  21.  
  22. 	const RENDERED_LABEL = 'MD🠯';
  23. 	const SOURCE_LABEL = '.mdc';
  24.  
  25. 	const MAX_RENDER_ATTEMPTS = 50;
  26. 	const RENDER_RETRY_INTERVAL = 100;
  27.  
  28. 	const RENDERED_ID = 'client-side-mdc-markdown';
  29.  
  30. 	let currentUrl = location.href;
  31. 	let isActive = false;
  32. 	let textareaObserver = null;
  33.  
  34. 	GM_addStyle(`
  35. 		#client-side-mdc-markdown {
  36. 			box-sizing: border-box;
  37. 			min-width: 200px;
  38. 			max-width: 980px;
  39. 			margin: 24px auto 0;
  40. 			padding: 45px;
  41. 			word-wrap: break-word;
  42. 		}
  43. 	`);
  44.  
  45. 	/**
  46. 	 * Processes MDC content by extracting YAML frontmatter and converting it to a code block
  47. 	 * @param {string} content - Raw MDC file content
  48. 	 * @returns {string} Processed content with YAML frontmatter as code block
  49. 	 */
  50. 	function processContent(content) {
  51. 		const match = content.match(YAML_FRONTMATTER_REGEX);
  52. 		if (match) {
  53. 			const [, yamlContent, markdownContent] = match;
  54. 			return `\`\`\`yaml\n${yamlContent}\n\`\`\`\n\n${markdownContent}`;
  55. 		}
  56. 		return content;
  57. 	}
  58.  
  59. 	/**
  60. 	 * Creates a button element with GitHub's styling
  61. 	 * @param {string} label - Button text content
  62. 	 * @param {string} mode - View mode ('rendered' or 'source')
  63. 	 * @param {boolean} isSelected - Whether button should be in selected state
  64. 	 * @returns {HTMLLIElement} Complete button list item element
  65. 	 */
  66. 	function createButton(label, mode, isSelected = false) {
  67. 		const li = document.createElement('li');
  68. 		li.className = `SegmentedControl-item${isSelected ? ' SegmentedControl-item--selected' : ''}`;
  69. 		li.setAttribute('role', 'listitem');
  70.  
  71. 		const button = document.createElement('button');
  72. 		button.setAttribute('aria-current', isSelected.toString());
  73. 		button.setAttribute('type', 'button');
  74. 		button.setAttribute('data-view-component', 'true');
  75. 		button.className = 'Button--invisible Button--small Button Button--invisible-noVisuals';
  76. 		button.onclick = () => setViewMode(mode);
  77.  
  78. 		const content = document.createElement('span');
  79. 		content.className = 'Button-content';
  80. 		const labelSpan = document.createElement('span');
  81. 		labelSpan.className = 'Button-label';
  82. 		labelSpan.setAttribute('data-content', label);
  83. 		labelSpan.textContent = label;
  84.  
  85. 		content.appendChild(labelSpan);
  86. 		button.appendChild(content);
  87. 		li.appendChild(button);
  88.  
  89. 		return li;
  90. 	}
  91.  
  92. 	/**
  93. 	 * Creates a GitHub-styled segmented control for toggling between rendered and source views
  94. 	 * @returns {HTMLDivElement} Complete toggle button control
  95. 	 */
  96. 	function createToggleButton() {
  97. 		const container = document.createElement('div');
  98. 		container.className = 'mdc-segmented-control';
  99.  
  100. 		const segmentedControl = document.createElement('segmented-control');
  101. 		segmentedControl.setAttribute('data-catalyst', '');
  102.  
  103. 		const ul = document.createElement('ul');
  104. 		ul.setAttribute('aria-label', 'MDC view');
  105. 		ul.setAttribute('role', 'list');
  106. 		ul.setAttribute('data-view-component', 'true');
  107. 		ul.className = 'SegmentedControl--small SegmentedControl';
  108.  
  109. 		ul.appendChild(createButton(RENDERED_LABEL, 'rendered', true));
  110. 		ul.appendChild(createButton(SOURCE_LABEL, 'source', false));
  111.  
  112. 		segmentedControl.appendChild(ul);
  113. 		container.appendChild(segmentedControl);
  114.  
  115. 		return container;
  116. 	}
  117.  
  118. 	/**
  119. 	 * Switches between rendered markdown and source code views
  120. 	 * @param {'rendered'|'source'} mode - View mode to activate
  121. 	 */
  122. 	function setViewMode(mode) {
  123. 		const rendered = document.getElementById(RENDERED_ID);
  124. 		const original = document.querySelector('#read-only-cursor-text-area')?.closest('section');
  125. 		const buttons = document.querySelectorAll('.mdc-segmented-control .SegmentedControl-item');
  126.  
  127. 		if (!rendered || !original || buttons.length !== 2) return;
  128.  
  129. 		const [renderedItem, sourceItem] = buttons;
  130. 		const renderedButton = renderedItem.querySelector('button');
  131. 		const sourceButton = sourceItem.querySelector('button');
  132.  
  133. 		const isRenderedMode = mode === 'rendered';
  134.  
  135. 		rendered.style.display = isRenderedMode ? 'block' : 'none';
  136. 		original.style.display = isRenderedMode ? 'none' : 'block';
  137.  
  138. 		renderedItem.classList.toggle('SegmentedControl-item--selected', isRenderedMode);
  139. 		sourceItem.classList.toggle('SegmentedControl-item--selected', !isRenderedMode);
  140.  
  141. 		if (renderedButton) renderedButton.setAttribute('aria-current', isRenderedMode.toString());
  142. 		if (sourceButton) sourceButton.setAttribute('aria-current', (!isRenderedMode).toString());
  143. 	}
  144.  
  145. 	/**
  146. 	 * Renders MDC content as HTML and inserts it into the page
  147. 	 * @returns {boolean} True if rendering was successful, false otherwise
  148. 	 */
  149. 	function renderMDC() {
  150. 		const textarea = document.querySelector('#read-only-cursor-text-area');
  151. 		if (!textarea) {
  152. 			DEBUG && console.log('[mdc-lite] No textarea found');
  153. 			return false;
  154. 		}
  155.  
  156. 		const content = textarea.textContent?.trim();
  157. 		if (!content) {
  158. 			DEBUG && console.log('[mdc-lite] No content in textarea');
  159. 			return false;
  160. 		}
  161.  
  162. 		const existing = document.getElementById(RENDERED_ID);
  163. 		existing?.remove();
  164.  
  165. 		const processedContent = processContent(content);
  166. 		const rendered = document.createElement('div');
  167. 		rendered.id = RENDERED_ID;
  168. 		rendered.className = 'markdown-body';
  169. 		rendered.innerHTML = marked.parse(processedContent);
  170.  
  171. 		rendered.querySelectorAll('pre code').forEach(block => {
  172. 			hljs.highlightElement(block);
  173. 		});
  174.  
  175. 		const section = textarea.closest('section');
  176. 		if (!section?.parentElement) {
  177. 			DEBUG && console.log('[mdc-lite] Could not find section to insert rendered content');
  178. 			return false;
  179. 		}
  180.  
  181. 		section.parentElement.insertBefore(rendered, section);
  182. 		section.style.display = 'none';
  183.  
  184. 		const toolbar = document.querySelector('.react-blob-header-edit-and-raw-actions');
  185. 		if (toolbar && !toolbar.querySelector('.mdc-segmented-control')) {
  186. 			toolbar.insertBefore(createToggleButton(), toolbar.firstChild);
  187. 		}
  188.  
  189. 		// Ensure toggle reflects actual display state (always rendered initially)
  190. 		setViewMode('rendered');
  191.  
  192. 		DEBUG && console.log('[mdc-lite] Successfully rendered MDC');
  193. 		return true;
  194. 	}
  195.  
  196. 	/**
  197. 	 * Removes all MDC-related elements and restores original state
  198. 	 */
  199. 	function cleanup() {
  200. 		document.getElementById(RENDERED_ID)?.remove();
  201. 		document.querySelector('.mdc-segmented-control')?.remove();
  202.  
  203. 		const original = document.querySelector('#read-only-cursor-text-area')?.closest('section');
  204. 		if (original) original.style.display = 'block';
  205.  
  206. 		if (textareaObserver) {
  207. 			textareaObserver.disconnect();
  208. 			textareaObserver = null;
  209. 		}
  210.  
  211. 		isActive = false;
  212. 		DEBUG && console.log('[mdc-lite] Cleaned up');
  213. 	}
  214.  
  215. 	/**
  216. 	 * Sets up a MutationObserver to watch for textarea content changes and re-render accordingly
  217. 	 * @returns {boolean} True if observer was successfully set up, false otherwise
  218. 	 */
  219. 	function setupTextareaObserver() {
  220. 		const textarea = document.querySelector('#read-only-cursor-text-area');
  221. 		if (!textarea) return false;
  222.  
  223. 		textareaObserver?.disconnect();
  224.  
  225. 		textareaObserver = new MutationObserver(() => {
  226. 			DEBUG && console.log('[mdc-lite] Textarea content changed, re-rendering');
  227. 			renderMDC();
  228. 		});
  229.  
  230. 		textareaObserver.observe(textarea, {
  231. 			childList: true,
  232. 			subtree: true,
  233. 			characterData: true
  234. 		});
  235.  
  236. 		DEBUG && console.log('[mdc-lite] Textarea observer set up');
  237. 		return true;
  238. 	}
  239.  
  240. 	/**
  241. 	 * Handles page navigation changes, activating or deactivating MDC rendering based on URL
  242. 	 */
  243. 	function handlePageChange() {
  244. 		if (MDC_FILE_REGEX.test(location.href)) {
  245. 			if (!isActive) {
  246. 				DEBUG && console.log('[mdc-lite] MDC file detected:', location.href);
  247. 				isActive = true;
  248.  
  249. 				if (renderMDC()) {
  250. 					setupTextareaObserver();
  251. 				} else {
  252. 					// Content not ready yet - retry with exponential backoff would be better, but keeping simple
  253. 					let attempts = 0;
  254.  
  255. 					const interval = setInterval(() => {
  256. 						attempts++;
  257. 						if (renderMDC()) {
  258. 							clearInterval(interval);
  259. 							setupTextareaObserver();
  260. 						} else if (attempts >= MAX_RENDER_ATTEMPTS) {
  261. 							clearInterval(interval);
  262. 							DEBUG && console.log('[mdc-lite] Timeout waiting for content');
  263. 						}
  264. 					}, RENDER_RETRY_INTERVAL);
  265. 				}
  266. 			} else {
  267. 				// SPA navigation to another MDC file - re-render to sync toggle state
  268. 				if (renderMDC()) {
  269. 					setupTextareaObserver();
  270. 				}
  271. 			}
  272. 		} else if (isActive) {
  273. 			cleanup();
  274. 		}
  275. 	}
  276.  
  277. 	/**
  278. 	 * Initializes the userscript by setting up page change detection and handling the current page
  279. 	 */
  280. 	function init() {
  281. 		handlePageChange();
  282.  
  283. 		// Monitor for SPA navigation changes
  284. 		new MutationObserver(() => {
  285. 			if (location.href !== currentUrl) {
  286. 				currentUrl = location.href;
  287. 				DEBUG && console.log('[mdc-lite] Navigation detected:', currentUrl);
  288. 				handlePageChange();
  289. 			}
  290. 		}).observe(document, { subtree: true, childList: true });
  291.  
  292. 		DEBUG && console.log('[mdc-lite] Initialized');
  293. 	}
  294.  
  295. 	if (document.readyState === 'loading') {
  296. 		document.addEventListener('DOMContentLoaded', init);
  297. 	} else {
  298. 		init();
  299. 	}
  300.  
  301. })();