1 files changed, 200 insertions, 0 deletions
diff --git a/packages/markdown/remark/src/index.ts b/packages/markdown/remark/src/index.ts
new file mode 100644
index 000000000..1aa713956
--- /dev/null
+++ b/packages/markdown/remark/src/index.ts
@@ -0,0 +1,200 @@
+import type {
+	AstroMarkdownOptions,
+	AstroMarkdownProcessorOptions,
+	MarkdownProcessor,
+	SyntaxHighlightConfig,
+} from './types.js';
+
+import { loadPlugins } from './load-plugins.js';
+import { rehypeHeadingIds } from './rehype-collect-headings.js';
+import { rehypePrism } from './rehype-prism.js';
+import { rehypeShiki } from './rehype-shiki.js';
+import { remarkCollectImages } from './remark-collect-images.js';
+
+import rehypeRaw from 'rehype-raw';
+import rehypeStringify from 'rehype-stringify';
+import remarkGfm from 'remark-gfm';
+import remarkParse from 'remark-parse';
+import remarkRehype from 'remark-rehype';
+import remarkSmartypants from 'remark-smartypants';
+import { unified } from 'unified';
+import { VFile } from 'vfile';
+import { defaultExcludeLanguages } from './highlight.js';
+import { rehypeImages } from './rehype-images.js';
+export { rehypeHeadingIds } from './rehype-collect-headings.js';
+export { remarkCollectImages } from './remark-collect-images.js';
+export { rehypePrism } from './rehype-prism.js';
+export { rehypeShiki } from './rehype-shiki.js';
+export {
+	isFrontmatterValid,
+	extractFrontmatter,
+	parseFrontmatter,
+	type ParseFrontmatterOptions,
+	type ParseFrontmatterResult,
+} from './frontmatter.js';
+export {
+	createShikiHighlighter,
+	type ShikiHighlighter,
+	type CreateShikiHighlighterOptions,
+	type ShikiHighlighterHighlightOptions,
+} from './shiki.js';
+export * from './types.js';
+
+export const syntaxHighlightDefaults: Required<SyntaxHighlightConfig> = {
+	type: 'shiki',
+	excludeLangs: defaultExcludeLanguages,
+};
+
+export const markdownConfigDefaults: Required<AstroMarkdownOptions> = {
+	syntaxHighlight: syntaxHighlightDefaults,
+	shikiConfig: {
+		langs: [],
+		theme: 'github-dark',
+		themes: {},
+		wrap: false,
+		transformers: [],
+		langAlias: {},
+	},
+	remarkPlugins: [],
+	rehypePlugins: [],
+	remarkRehype: {},
+	gfm: true,
+	smartypants: true,
+};
+
+// Skip nonessential plugins during performance benchmark runs
+const isPerformanceBenchmark = Boolean(process.env.ASTRO_PERFORMANCE_BENCHMARK);
+
+/**
+ * Create a markdown preprocessor to render multiple markdown files
+ */
+export async function createMarkdownProcessor(
+	opts?: AstroMarkdownProcessorOptions,
+): Promise<MarkdownProcessor> {
+	const {
+		syntaxHighlight = markdownConfigDefaults.syntaxHighlight,
+		shikiConfig = markdownConfigDefaults.shikiConfig,
+		remarkPlugins = markdownConfigDefaults.remarkPlugins,
+		rehypePlugins = markdownConfigDefaults.rehypePlugins,
+		remarkRehype: remarkRehypeOptions = markdownConfigDefaults.remarkRehype,
+		gfm = markdownConfigDefaults.gfm,
+		smartypants = markdownConfigDefaults.smartypants,
+		experimentalHeadingIdCompat = false,
+	} = opts ?? {};
+
+	const loadedRemarkPlugins = await Promise.all(loadPlugins(remarkPlugins));
+	const loadedRehypePlugins = await Promise.all(loadPlugins(rehypePlugins));
+
+	const parser = unified().use(remarkParse);
+
+	// gfm and smartypants
+	if (!isPerformanceBenchmark) {
+		if (gfm) {
+			parser.use(remarkGfm);
+		}
+		if (smartypants) {
+			parser.use(remarkSmartypants);
+		}
+	}
+
+	// User remark plugins
+	for (const [plugin, pluginOpts] of loadedRemarkPlugins) {
+		parser.use(plugin, pluginOpts);
+	}
+
+	if (!isPerformanceBenchmark) {
+		// Apply later in case user plugins resolve relative image paths
+		parser.use(remarkCollectImages, opts?.image);
+	}
+
+	// Remark -> Rehype
+	parser.use(remarkRehype, {
+		allowDangerousHtml: true,
+		passThrough: [],
+		...remarkRehypeOptions,
+	});
+
+	if (syntaxHighlight && !isPerformanceBenchmark) {
+		const syntaxHighlightType =
+			typeof syntaxHighlight === 'string' ? syntaxHighlight : syntaxHighlight?.type;
+		const excludeLangs =
+			typeof syntaxHighlight === 'object' ? syntaxHighlight?.excludeLangs : undefined;
+		// Syntax highlighting
+		if (syntaxHighlightType === 'shiki') {
+			parser.use(rehypeShiki, shikiConfig, excludeLangs);
+		} else if (syntaxHighlightType === 'prism') {
+			parser.use(rehypePrism, excludeLangs);
+		}
+	}
+
+	// User rehype plugins
+	for (const [plugin, pluginOpts] of loadedRehypePlugins) {
+		parser.use(plugin, pluginOpts);
+	}
+
+	// Images / Assets support
+	parser.use(rehypeImages);
+
+	// Headings
+	if (!isPerformanceBenchmark) {
+		parser.use(rehypeHeadingIds, { experimentalHeadingIdCompat });
+	}
+
+	// Stringify to HTML
+	parser.use(rehypeRaw).use(rehypeStringify, { allowDangerousHtml: true });
+
+	return {
+		async render(content, renderOpts) {
+			const vfile = new VFile({
+				value: content,
+				path: renderOpts?.fileURL,
+				data: {
+					astro: {
+						frontmatter: renderOpts?.frontmatter ?? {},
+					},
+				},
+			});
+
+			const result = await parser.process(vfile).catch((err) => {
+				// Ensure that the error message contains the input filename
+				// to make it easier for the user to fix the issue
+				err = prefixError(err, `Failed to parse Markdown file "${vfile.path}"`);
+				console.error(err);
+				throw err;
+			});
+
+			return {
+				code: String(result.value),
+				metadata: {
+					headings: result.data.astro?.headings ?? [],
+					localImagePaths: result.data.astro?.localImagePaths ?? [],
+					remoteImagePaths: result.data.astro?.remoteImagePaths ?? [],
+					frontmatter: result.data.astro?.frontmatter ?? {},
+				},
+			};
+		},
+	};
+}
+
+function prefixError(err: any, prefix: string) {
+	// If the error is an object with a `message` property, attempt to prefix the message
+	if (err?.message) {
+		try {
+			err.message = `${prefix}:\n${err.message}`;
+			return err;
+		} catch {
+			// Any errors here are ok, there's fallback code below
+		}
+	}
+
+	// If that failed, create a new error with the desired message and attempt to keep the stack
+	const wrappedError = new Error(`${prefix}${err ? `: ${err}` : ''}`);
+	try {
+		wrappedError.stack = err.stack;
+		wrappedError.cause = err;
+	} catch {
+		// It's ok if we could not set the stack or cause - the message is the most important part
+	}
+
+	return wrappedError;
+}