From 639fccae7f814eaa2714354aaa516a85cc8c4ebf Mon Sep 17 00:00:00 2001
From: Hyeseong Kim <hey@hyeseong.kim>
Date: Fri, 3 Sep 2021 15:46:17 +0900
Subject: [PATCH] fix(server): fix collect to ignore empty class (#832)

---
 packages/server/__tests__/collect.test.ts | 17 +++++++++++++++++
 packages/server/src/collect.ts            |  2 +-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/packages/server/__tests__/collect.test.ts b/packages/server/__tests__/collect.test.ts
index ba5208e68..18195fca2 100644
--- a/packages/server/__tests__/collect.test.ts
+++ b/packages/server/__tests__/collect.test.ts
@@ -233,3 +233,20 @@ describe('include atrule once', () => {
   test('critical', () => expect(prettyPrint(critical)).toMatchSnapshot());
   test('other', () => expect(prettyPrint(other)).toMatchSnapshot());
 });
+
+describe('ignore empty class attribute', () => {
+  const html = dedent`
+    <div class=""></div>
+    <div class="a"></div>
+    <div class=""></div>
+    <div class="b"></div>
+    <div class=""></div>
+  `;
+
+  const css = dedent`
+    .not-exist {}
+  `;
+
+  const { critical } = collect(html, css);
+  test('critical should be empty', () => expect(critical).toEqual(''));
+});
diff --git a/packages/server/src/collect.ts b/packages/server/src/collect.ts
index 5d2b19715..2859b38a1 100644
--- a/packages/server/src/collect.ts
+++ b/packages/server/src/collect.ts
@@ -97,7 +97,7 @@ export default function collect(html: string, css: string): CollectResult {
 
 const extractClassesFromHtml = (html: string): RegExp => {
   const htmlClasses: string[] = [];
-  const regex = /\s+class="([^"]*)"/gm;
+  const regex = /\s+class="([^"]+)"/gm;
   let match = regex.exec(html);
 
   while (match !== null) {