remove some unnecessary markdown transformation indirection (#285)

Author: Rich-Harris

packages/site-kit/src/lib/markdown/renderer.ts

@@ -148,15 +148,48 @@ export async function render_content_markdown(
 		}
 	}
 
-	return parse({
-		body,
-		type_links,
-		code: (raw, language, current) => {
-			const cached_snippet = SNIPPET_CACHE.get(raw + language + current);
+	const headings: string[] = [];
+
+	// this is a bit hacky, but it allows us to prevent type declarations
+	// from linking to themselves
+	let current = '';
+
+	return await transform(body, {
+		text(token) {
+			// @ts-expect-error I think this is a bug in marked — some text tokens have children,
+			// but that's not reflected in the types. In these cases we can't just use `token.tokens`
+			// because that will result in e.g. `<code>` elements not being generated
+			if (token.tokens) {
+				// @ts-expect-error
+				return this.parser!.parseInline(token.tokens);
+			}
+
+			return smart_quotes(token.text, true);
+		},
+		heading({ tokens, depth, raw }) {
+			const text = this.parser!.parseInline(tokens);
+
+			const title = text
+				.replace(/<\/?code>/g, '')
+				.replace(/&quot;/g, '"')
+				.replace(/&lt;/g, '<')
+				.replace(/&gt;/g, '>');
+			current = title;
+			const normalized = normalizeSlugify(raw);
+			headings[depth - 1] = normalized;
+			headings.length = depth;
+			const slug = headings.filter(Boolean).join('-');
+			return `<h${depth} id="${slug}">${text.replace(
+				/<\/?code>/g,
+				''
+			)}<a href="#${slug}" class="permalink"><span class="visually-hidden">permalink</span></a></h${depth}>`;
+		},
+		code({ text, lang = 'js' }) {
+			const cached_snippet = SNIPPET_CACHE.get(text + lang + current);
 			if (cached_snippet.code) return cached_snippet.code;
 
-			let { source, options } = parse_options(raw, language);
-			source = adjust_tab_indentation(source, language);
+			let { source, options } = parse_options(text, lang);
+			source = adjust_tab_indentation(source, lang);
 
 			const converted = conversions.get(source);
 
@@ -182,7 +215,7 @@ export async function render_content_markdown(
 			html += syntax_highlight({
 				filename,
 				highlighter,
-				language,
+				language: lang,
 				source,
 				twoslashBanner,
 				options
@@ -192,7 +225,7 @@ export async function render_content_markdown(
 				html += syntax_highlight({
 					filename,
 					highlighter,
-					language: language === 'js' ? 'ts' : language,
+					language: lang === 'js' ? 'ts' : lang,
 					source: converted,
 					twoslashBanner,
 					options
@@ -225,7 +258,7 @@ export async function render_content_markdown(
 
 			return html;
 		},
-		codespan: (text) => {
+		codespan({ text }) {
 			return (
 				'<code>' +
 				(type_regex
@@ -238,61 +271,6 @@ export async function render_content_markdown(
 					: text) +
 				'</code>'
 			);
-		}
-	});
-}
-
-async function parse({
-	body,
-	code,
-	codespan
-}: {
-	body: string;
-	type_links: Map<string, { relativeURL: string; slug: string; page: string }> | null;
-	code: (source: string, language: string, current: string) => string;
-	codespan: (source: string) => string;
-}) {
-	const headings: string[] = [];
-
-	// this is a bit hacky, but it allows us to prevent type declarations
-	// from linking to themselves
-	let current = '';
-
-	return await transform(body, {
-		text(token) {
-			// @ts-expect-error I think this is a bug in marked — some text tokens have children,
-			// but that's not reflected in the types. In these cases we can't just use `token.tokens`
-			// because that will result in e.g. `<code>` elements not being generated
-			if (token.tokens) {
-				// @ts-expect-error
-				return this.parser!.parseInline(token.tokens);
-			}
-
-			return smart_quotes(token.text, true);
-		},
-		heading({ tokens, depth, raw }) {
-			const text = this.parser!.parseInline(tokens);
-
-			const title = text
-				.replace(/<\/?code>/g, '')
-				.replace(/&quot;/g, '"')
-				.replace(/&lt;/g, '<')
-				.replace(/&gt;/g, '>');
-			current = title;
-			const normalized = normalizeSlugify(raw);
-			headings[depth - 1] = normalized;
-			headings.length = depth;
-			const slug = headings.filter(Boolean).join('-');
-			return `<h${depth} id="${slug}">${text.replace(
-				/<\/?code>/g,
-				''
-			)}<a href="#${slug}" class="permalink"><span class="visually-hidden">permalink</span></a></h${depth}>`;
-		},
-		code({ text, lang }) {
-			return code(text, lang ?? 'js', current);
-		},
-		codespan({ text }) {
-			return codespan(text);
 		},
 		blockquote(token) {
 			let content = this.parser?.parse(token.tokens) ?? '';