perf: optimize route transitions using React startTransition

Author: sanjaiyan-dev

packages/core/src/theme/components/DocContent/docComponents/a.tsx

@@ -1,6 +1,14 @@
 import { Link } from '@rspress/core/theme';
-import type { ComponentProps } from 'react';
+import { startTransition, type ComponentProps } from 'react';
+import { useSite } from '@rspress/core/runtime';
 
 export const A = (props: ComponentProps<'a'>) => {
-  return <Link {...props} />;
+  const siteData = useSite();
+  const concurrentRoute = siteData?.site?.route?.concurrentRoute;
+  return (
+    <Link
+      startTransition={concurrentRoute ? startTransition : undefined}
+      {...props}
+    />
+  );
 };

packages/shared/src/types/index.ts

@@ -503,6 +503,13 @@ export interface RouteOptions {
    * @default false
    */
   cleanUrls?: boolean;
+  /**
+   * Enable concurrent, optimized routing for markdown links.
+   * Only applies to links located inside `.md` and `.mdx` files.
+   * @default false
+   * @unstable
+   */
+  concurrentRoute?: boolean;
 }
 
 export interface SearchHooks {