Improve local link transform plugin

astro.config.mjs

@@ -1,5 +1,6 @@
 import { defineConfig } from 'astro/config';
 import starlight from '@astrojs/starlight';
+import transformLocalLinks from "./src/plugins/transformLocalLinks.js";
 
 const defaultConfig = {
 	title: 'Code0 Documentation'
@@ -9,28 +10,6 @@ const config = process.env.SRC_DIR
 	? (await import(/* @vite-ignore */`${process.env.SRC_DIR}/docs/starlight.json`)).default
 	: defaultConfig;
 
-const transformLocalLinks = () => {
-	return {
-		name: 'transform-local-links',
-
-		transform(src, id) {
-			if (id.endsWith('.md') || id.endsWith('.mdx')) {
-				const directory = id.endsWith('index.md') || id.endsWith('index.mdx') ? '' : '../';
-
-				const code = src
-					.replaceAll(/\[([^\]]+?)]\(([^)]+?)\.mdx?\)/g, `[$1](${directory}$2/)`)
-					.replaceAll(/href=\\"([^"]+?)\.mdx?\\"/g, `href=\\"${directory}$1/\\"`)
-					.replaceAll(/href: "([^"]+?)\.mdx?"/g, `href: "${directory}$1/"`);
-
-				return {
-					code: code,
-					map: null, // provide source map if available
-				}
-			}
-		},
-	}
-}
-
 // https://astro.build/config
 export default defineConfig({
 	base: process.env.BASE_URL,

src/plugins/transformLocalLinks.js

@@ -0,0 +1,35 @@
+const replaceUrl = (directoryPrefix) => (match, fullUrl, matchedUrl) => {
+    if(new URL(fullUrl, 'https://docs.code0.tech').origin !== 'https://docs.code0.tech') {
+        // not a relative url
+        return match;
+    }
+
+    let replacementUrl = matchedUrl;
+
+    if(/(?:^|\/)index$/.test(matchedUrl)) {
+        replacementUrl = matchedUrl === 'index' ? '' : matchedUrl.replace(/\/index/, '');
+    }
+
+    return match.replace(fullUrl, `${directoryPrefix}${replacementUrl}/`.replace('//', ''))
+}
+
+export default () => ({
+    name: 'transform-local-links',
+
+    transform(src, id) {
+        if (id.endsWith('.md') || id.endsWith('.mdx')) {
+            const directory = id.endsWith('index.md') || id.endsWith('index.mdx') ? '' : '../';
+
+            const regexes = [
+                /\[[^\]]+?]\((([^)]+?)\.mdx?)\)/g,
+                /href=\\"(([^"]+?)\.mdx?)\\"/g,
+                /href: "(([^"]+?)\.mdx?)"/g
+            ]
+
+            return {
+                code: regexes.reduce((acc, regex) => acc.replaceAll(regex, replaceUrl(directory)), src),
+                map: null
+            }
+        }
+    },
+})