From ce22ca07fffc890191893405790b6e49b9de724a Mon Sep 17 00:00:00 2001
From: "Sakamoto, Kazunori" <exkazuu@gmail.com>
Date: Sun, 13 Sep 2026 21:41:59 +0900
Subject: [PATCH] perf: defer HTML formatter imports for browser graders

Co-authored-by: WillBooster (Codex CLI) <agent@willbooster.com>
---
 packages/problem-utils-browser/src/html.ts | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/packages/problem-utils-browser/src/html.ts b/packages/problem-utils-browser/src/html.ts
index 25e0a99..0214f99 100644
--- a/packages/problem-utils-browser/src/html.ts
+++ b/packages/problem-utils-browser/src/html.ts
@@ -10,10 +10,7 @@ import {
   startLocalHttpServer,
   type TestCaseResult,
 } from '@exercode/problem-utils';
-import sniffHtmlEncoding from 'html-encoding-sniffer';
 import type { Page } from 'puppeteer';
-import { format } from 'prettier';
-import prettierPluginOrganizeAttributes from 'prettier-plugin-organize-attributes';
 
 import { createBrowserPage, capturePngScreenshot, launchBrowser } from './browser.js';
 import { createTemporaryDirectory } from './temporaryDirectory.js';
@@ -258,6 +255,12 @@ async function loadFormattedHtmlForScreenshot(url: string): Promise<string | und
     if (!contentType.includes('text/html')) return undefined;
 
     const bytes = new Uint8Array(await response.arrayBuffer());
+    const [{ default: sniffHtmlEncoding }, { format }, { default: prettierPluginOrganizeAttributes }] =
+      await Promise.all([
+        import('html-encoding-sniffer'),
+        import('prettier'),
+        import('prettier-plugin-organize-attributes'),
+      ]);
     const encoding = sniffHtmlEncoding(bytes, {
       transportLayerEncodingLabel: new MIMEType(contentType).params.get('charset') ?? undefined,
       defaultEncoding: 'utf8',