From e43f203a2ac1c86556cb0ca74b667efdbc6b883b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?TATSUNO=20=E2=80=9CTaz=E2=80=9D=20Yasuhiro?=
 <ytatsuno.jp@gmail.com>
Date: Sun, 3 Nov 2024 07:58:31 +0900
Subject: [PATCH] perf(helper/cookie): fast-path for name specified (#3608)

* perf(helper/cookie): fast-path for a specific key

* perf(helper/cookie): fast-path for a specific key not found

* perf(helper/cookie): added test for missing case

* perf(helper/cookie): fix tests

* perf(helper/cookie): fix tests

* perf(helper/cookie): cleanup tests
---
 src/utils/cookie.test.ts |  8 ++++++++
 src/utils/cookie.ts      | 20 ++++++++++++++------
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/src/utils/cookie.test.ts b/src/utils/cookie.test.ts
index 84578a9c..d8ba7e51 100644
--- a/src/utils/cookie.test.ts
+++ b/src/utils/cookie.test.ts
@@ -30,6 +30,14 @@ describe('Parse cookie', () => {
     expect(cookie['tasty_cookie']).toBeUndefined()
   })
 
+  it('Should parse one cookie specified by name even if it is not found', () => {
+    const cookieString = 'yummy_cookie=choco; tasty_cookie = strawberry '
+    const cookie: Cookie = parse(cookieString, 'no_such_cookie')
+    expect(cookie['yummy_cookie']).toBeUndefined()
+    expect(cookie['tasty_cookie']).toBeUndefined()
+    expect(cookie['no_such_cookie']).toBeUndefined()
+  })
+
   it('Should parse cookies with no value', () => {
     const cookieString = 'yummy_cookie=; tasty_cookie = ; best_cookie= ; last_cookie=""'
     const cookie: Cookie = parse(cookieString)
diff --git a/src/utils/cookie.ts b/src/utils/cookie.ts
index 45797ddf..16986667 100644
--- a/src/utils/cookie.ts
+++ b/src/utils/cookie.ts
@@ -77,17 +77,22 @@ const validCookieNameRegEx = /^[\w!#$%&'*.^`|~+-]+$/
 const validCookieValueRegEx = /^[ !#-:<-[\]-~]*$/
 
 export const parse = (cookie: string, name?: string): Cookie => {
+  if (name && cookie.indexOf(name) === -1) {
+    // Fast-path: return immediately if the demanded-key is not in the cookie string
+    return {}
+  }
   const pairs = cookie.trim().split(';')
-  return pairs.reduce((parsedCookie, pairStr) => {
+  const parsedCookie: Cookie = {}
+  for (let pairStr of pairs) {
     pairStr = pairStr.trim()
     const valueStartPos = pairStr.indexOf('=')
     if (valueStartPos === -1) {
-      return parsedCookie
+      continue
     }
 
     const cookieName = pairStr.substring(0, valueStartPos).trim()
     if ((name && name !== cookieName) || !validCookieNameRegEx.test(cookieName)) {
-      return parsedCookie
+      continue
     }
 
     let cookieValue = pairStr.substring(valueStartPos + 1).trim()
@@ -96,10 +101,13 @@ export const parse = (cookie: string, name?: string): Cookie => {
     }
     if (validCookieValueRegEx.test(cookieValue)) {
       parsedCookie[cookieName] = decodeURIComponent_(cookieValue)
+      if (name) {
+        // Fast-path: return only the demanded-key immediately. Other keys are not needed.
+        break
+      }
     }
-
-    return parsedCookie
-  }, {} as Cookie)
+  }
+  return parsedCookie
 }
 
 export const parseSigned = async (