From 47917c9c2c56887c53d68e23159a7e1c3f7cb958 Mon Sep 17 00:00:00 2001
From: Blake Embrey <hello@blakeembrey.com>
Date: Wed, 2 Oct 2024 14:56:24 -0700
Subject: [PATCH] Iterate whitespace for perf (#170)

---
 index.js      | 55 +++++++++++++++++++++++++++++++++++++--------------
 test/parse.js | 17 +++++++++++++++-
 2 files changed, 56 insertions(+), 16 deletions(-)

diff --git a/index.js b/index.js
index 6fe633d..0eeccaf 100644
--- a/index.js
+++ b/index.js
@@ -95,40 +95,49 @@ function parse(str, options) {
     throw new TypeError('argument str must be a string');
   }
 
-  var obj = {}
+  var obj = {};
   var opt = options || {};
   var dec = opt.decode || decode;
 
-  var index = 0
-  while (index < str.length) {
-    var eqIdx = str.indexOf('=', index)
+  var index = 0;
+  var eqIdx = 0;
+  var endIdx = 0;
+  var len = str.length;
+  var max = len - 2;
+
+  while (index < max) {
+    eqIdx = str.indexOf('=', index);
 
     // no more cookie pairs
     if (eqIdx === -1) {
-      break
+      break;
     }
 
-    var endIdx = str.indexOf(';', index)
+    endIdx = str.indexOf(';', index);
 
     if (endIdx === -1) {
-      endIdx = str.length
-    } else if (endIdx < eqIdx) {
+      endIdx = len;
+    } else if (eqIdx > endIdx) {
       // backtrack on prior semicolon
-      index = str.lastIndexOf(';', eqIdx - 1) + 1
-      continue
+      index = str.lastIndexOf(';', eqIdx - 1) + 1;
+      continue;
     }
 
-    var key = str.slice(index, eqIdx).trim()
+    var keyStartIdx = startIndex(str, index, eqIdx);
+    var keyEndIdx = endIndex(str, eqIdx, keyStartIdx);
+    var key = str.slice(keyStartIdx, keyEndIdx);
 
     // only assign once
     if (undefined === obj[key]) {
-      var val = str.slice(eqIdx + 1, endIdx).trim()
+      var valStartIdx = startIndex(str, eqIdx + 1, endIdx);
+      var valEndIdx = endIndex(str, endIdx, valStartIdx);
 
-      // quoted values
-      if (val.charCodeAt(0) === 0x22) {
-        val = val.slice(1, -1)
+      if (str.charCodeAt(valStartIdx) === 0x22 /* " */ && str.charCodeAt(valEndIdx - 1) === 0x22 /* " */) {
+        valStartIdx++;
+        valEndIdx--;
       }
 
+      var val = str.slice(valStartIdx, valEndIdx);
       obj[key] = tryDecode(val, dec);
     }
 
@@ -138,6 +147,22 @@ function parse(str, options) {
   return obj;
 }
 
+function startIndex(str, index, max) {
+  do {
+    var code = str.charCodeAt(index);
+    if (code !== 0x20 /*   */ && code !== 0x09 /* \t */) return index;
+  } while (++index < max);
+  return max;
+}
+
+function endIndex(str, index, min) {
+  while (index > min) {
+    var code = str.charCodeAt(--index);
+    if (code !== 0x20 /*   */ && code !== 0x09 /* \t */) return index + 1;
+  }
+  return min;
+}
+
 /**
  * Serialize data into a cookie header.
  *
diff --git a/test/parse.js b/test/parse.js
index 76229ca..c11b4fc 100644
--- a/test/parse.js
+++ b/test/parse.js
@@ -24,7 +24,7 @@ describe('cookie.parse(str)', function () {
   })
 
   it('should parse cookie with empty value', function () {
-    assert.deepEqual(cookie.parse('foo= ; bar='), { foo: '', bar: '' })
+    assert.deepEqual(cookie.parse('foo=; bar='), { foo: '', bar: '' })
   })
 
   it('should URL-decode values', function () {
@@ -34,6 +34,21 @@ describe('cookie.parse(str)', function () {
     assert.deepEqual(cookie.parse('email=%20%22%2c%3b%2f'), { email: ' ",;/' })
   })
 
+  it('should parse quoted values', function () {
+    assert.deepEqual(cookie.parse('foo="bar"'), { foo: 'bar' })
+    assert.deepEqual(cookie.parse('foo=" a b c "'), { foo: ' a b c ' })
+  })
+
+  it('should trim whitespace around key and value', function () {
+    assert.deepEqual(cookie.parse('  foo  =  "bar"  '), { foo: 'bar' })
+    assert.deepEqual(cookie.parse('  foo  =  bar  ;  fizz  =  buzz  '), { foo: 'bar', fizz: 'buzz' })
+    assert.deepEqual(cookie.parse(' foo = " a b c " '), { foo: ' a b c ' })
+    assert.deepEqual(cookie.parse(' = bar '), { '': 'bar' })
+    assert.deepEqual(cookie.parse(' foo = '), { foo: '' })
+    assert.deepEqual(cookie.parse('   =   '), { '': '' })
+    assert.deepEqual(cookie.parse('\tfoo\t=\tbar\t'), { foo: 'bar' })
+  })
+
   it('should return original value on escape error', function () {
     assert.deepEqual(cookie.parse('foo=%1;bar=bar'), { foo: '%1', bar: 'bar' })
   })