From c7a903a7991a39c3e44c55e86955ccf4f95e8a7c Mon Sep 17 00:00:00 2001
From: uzlopak <aras.abbasi@googlemail.com>
Date: Thu, 2 Feb 2023 21:06:11 +0100
Subject: [PATCH] improve performance of isUtf8MimeType

---
 benchmarks/isUtf8MimeType.js | 23 +++++++++++++++++++++++
 lib/isUtf8MimeType.js        | 10 ++++++++--
 test/isUtf8MimeType.test.js  | 22 ++++++++++++++++++++++
 3 files changed, 53 insertions(+), 2 deletions(-)
 create mode 100644 benchmarks/isUtf8MimeType.js
 create mode 100644 test/isUtf8MimeType.test.js

diff --git a/benchmarks/isUtf8MimeType.js b/benchmarks/isUtf8MimeType.js
new file mode 100644
index 0000000..a68a8bc
--- /dev/null
+++ b/benchmarks/isUtf8MimeType.js
@@ -0,0 +1,23 @@
+'use strict'
+
+const benchmark = require('benchmark')
+const isUtf8MimeType = require('../lib/isUtf8MimeType').isUtf8MimeType
+
+const applicationJson = 'application/json'
+const applicationJavascript = 'application/javascript'
+const textJson = 'text/json'
+const textHtml = 'text/html'
+const textJavascript = 'text/javascript'
+const imagePng = 'image/png'
+
+new benchmark.Suite()
+  .add('isUtf8MimeType', function () {
+    isUtf8MimeType(applicationJson)
+    isUtf8MimeType(applicationJavascript)
+    isUtf8MimeType(imagePng)
+    isUtf8MimeType(textJson)
+    isUtf8MimeType(textHtml)
+    isUtf8MimeType(textJavascript)
+  }, { minSamples: 100 })
+  .on('cycle', function onCycle (event) { console.log(String(event.target)) })
+  .run({ async: false })
diff --git a/lib/isUtf8MimeType.js b/lib/isUtf8MimeType.js
index 93a7c5b..d24978a 100644
--- a/lib/isUtf8MimeType.js
+++ b/lib/isUtf8MimeType.js
@@ -1,6 +1,12 @@
 'use strict'
 
-const utf8MimeTypeRE = /^text\/|^application\/(javascript|json)/
-const isUtf8MimeType = utf8MimeTypeRE.test.bind(utf8MimeTypeRE)
+function isUtf8MimeType (value) {
+  const len = value.length
+  return (
+    (len > 21 && value.indexOf('application/javascript') === 0) ||
+    (len > 14 && value.indexOf('application/json') === 0) ||
+    (len > 5 && value.indexOf('text/') === 0)
+  )
+}
 
 module.exports.isUtf8MimeType = isUtf8MimeType
diff --git a/test/isUtf8MimeType.test.js b/test/isUtf8MimeType.test.js
new file mode 100644
index 0000000..f718c2a
--- /dev/null
+++ b/test/isUtf8MimeType.test.js
@@ -0,0 +1,22 @@
+'use strict'
+
+const { test } = require('tap')
+const { isUtf8MimeType } = require('../lib/isUtf8MimeType')
+
+test('isUtf8MimeType', function (t) {
+  const testCases = [
+    ['application/json', true],
+    ['text/json', true],
+    ['application/javascript', true],
+    ['text/javascript', true],
+    ['application/json+v5', true],
+    ['text/xml', true],
+    ['text/html', true],
+    ['image/png', false]
+  ]
+  t.plan(testCases.length)
+
+  for (let i = 0; i < testCases.length; ++i) {
+    t.strictSame(isUtf8MimeType(testCases[i][0], 'test'), testCases[i][1])
+  }
+})