Core: fix edge case for Dynamic Link

.changeset/fast-ducks-talk.md

@@ -0,0 +1,5 @@
+---
+'fumadocs-core': patch
+---
+
+fix edge case for Dynamic Link

packages/core/src/dynamic-link.tsx

@@ -16,15 +16,7 @@ export const DynamicLink = forwardRef<HTMLAnchorElement, DynamicLinkProps>(
   ({ href, ...props }, ref) => {
     const params = useParams();
 
-    const url = useMemo(() => {
-      return href?.replace(/\[.*]/, (key) => {
-        const mappedKey = key.slice(1, -1);
-        const value = mappedKey in params ? params[mappedKey] : undefined;
-        if (!value) return '';
-
-        return typeof value === 'string' ? value : value.join('/');
-      });
-    }, [params, href]);
+    const url = useMemo(() => (href ? updateHref(href, params) : href), [params, href]);
 
     return <Link ref={ref} href={url} {...props} />;
   },
@@ -32,4 +24,15 @@ export const DynamicLink = forwardRef<HTMLAnchorElement, DynamicLinkProps>(
 
 DynamicLink.displayName = 'DynamicLink';
 
+export function updateHref(href: string, params: Record<string, string | string[]>) {
+  return href.replace(/\[(.*)]\/?/, (match, key) => {
+    const hasEndingSlash = match[match.length - 1] === '/';
+    const value = key in params ? params[key] : undefined;
+    if (!value) return '';
+
+    const replacement = typeof value === 'string' ? value : value.join('/');
+    return hasEndingSlash ? `${replacement}/` : replacement;
+  });
+}
+
 export default DynamicLink;

packages/core/test/index.test.ts

@@ -5,6 +5,7 @@ import { findNeighbour, findSiblings } from '@/page-tree/utils';
 import { getBreadcrumbItems } from '@/breadcrumb';
 import { DefaultFormatter } from '@/i18n/middleware';
 import { NextURL } from 'next/dist/server/web/next-url';
+import { updateHref } from '@/dynamic-link';
 
 test('Find Neighbours', () => {
   const tree: Root = {
@@ -199,3 +200,12 @@ test('findSiblings', () => {
     ]
   `);
 });
+
+test('Dynamic Link: update href', () => {
+  expect(updateHref('/[lang]/test', {})).toBe('/test');
+  expect(updateHref('/[lang]/test', { lang: 'en' })).toBe('/en/test');
+  expect(updateHref('/[lang]/test', { lang: ['en', 'cn'] })).toBe('/en/cn/test');
+
+  // relative -> relative
+  expect(updateHref('[lang]/test', {})).toBe('test');
+});