Small cleanups

- Error decoder: key the compiled-MDX cache on the error message instead
  of the entire codes.json map.
- Home page clock: tick on minute boundaries again instead of every 60s
  from mount.
- next.config: drop the @babel/* entries from serverExternalPackages; the
  server no longer uses Babel.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: gaearon

next.config.js

@@ -18,9 +18,6 @@ const nextConfig = {
   reactCompiler: true,
   cacheComponents: true,
   serverExternalPackages: [
-    '@babel/core',
-    '@babel/plugin-transform-modules-commonjs',
-    '@babel/preset-react',
     '@mdx-js/mdx',
     'gray-matter',
     'unist-util-visit',

src/components/Layout/HomeContent.js

@@ -95,14 +95,18 @@ function CurrentTime() {
 
   useEffect(() => {
     const msPerMinute = 60 * 1000;
+    let timeout;
 
     function updateDate() {
       setDate(new Date());
+      // Update on the minute, like the clock on a phone would.
+      const now = Date.now();
+      const nextMinute = (Math.floor(now / msPerMinute) + 1) * msPerMinute;
+      timeout = setTimeout(updateDate, nextMinute - now);
     }
 
     updateDate();
-    const interval = setInterval(updateDate, msPerMinute);
-    return () => clearInterval(interval);
+    return () => clearTimeout(timeout);
   }, []);
 
   const currentTime = date?.toLocaleTimeString([], {

src/lib/loadErrorDecoderData.ts

@@ -33,7 +33,7 @@ async function loadErrorCodes(): Promise<Record<string, string>> {
  */
 async function compileErrorDecoderData(
   code: string | null,
-  errorCodes: Record<string, string>
+  errorMessage: string | null
 ): Promise<ErrorDecoderData> {
   'use cache';
   cacheLife('max');
@@ -50,7 +50,7 @@ async function compileErrorDecoderData(
   return {
     ...compiled,
     errorCode: code,
-    errorMessage: code ? errorCodes[code] : null,
+    errorMessage,
   };
 }
 
@@ -61,7 +61,8 @@ export async function loadErrorDecoderData(
   if (code && !errorCodes[code]) {
     notFound();
   }
-  return compileErrorDecoderData(code, errorCodes);
+  // Only the message goes into the cache key, not the whole codes map.
+  return compileErrorDecoderData(code, code ? errorCodes[code] : null);
 }
 
 export async function listErrorCodes(): Promise<string[]> {