feat(plugin): add rehype-starry-night-inline plugin

src/rehype-starry-night-inline/index.js

@@ -0,0 +1,40 @@
+import defu from "defu";
+import { createStarryNight, all } from "@wooorm/starry-night";
+import { visit } from "unist-util-visit";
+import { toString } from "hast-util-to-string";
+
+const defaults = {
+	classNamePrefix: "hl"
+};
+
+export default function rehypeStarryNightInline(userOptions = {}) {
+	const { aliases = {}, grammars = all, classNamePrefix } = defu(userOptions, defaults);
+	const starryNightPromise = createStarryNight(grammars);
+
+	return async function (tree) {
+		const starryNight = await starryNightPromise;
+
+		visit(tree, "element", (node, index, parent) => {
+			const annotatedInlineCode = node.tagName === "code" && ("lang" in node.properties);
+
+			if (!parent || index === null || node.tagName !== "code" || !annotatedInlineCode) {
+				return;
+			}
+
+			const { lang, ...props } = node.properties;
+			const languageId = aliases[lang] || lang;
+			const scope = starryNight.flagToScope(languageId);
+
+			if (scope) {
+				const fragment = starryNight.highlight(toString(node), scope);
+				node.children = fragment.children;
+				node.properties = {
+					className: [`${classNamePrefix}-inline`, `${classNamePrefix}-${languageId}`],
+					...props
+				};
+			} else {
+				node.properties = props;
+			}
+		});
+	};
+}