perf: use regexp in string escaping (#553)

* perf: use regexp in string escaping * Add code comments for regexp check
fastify · Oct 27, 2022 · 357c1e3 · 357c1e3
1 parent f5f1623
commit 357c1e3
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/lib/serializer.js b/lib/serializer.js
@@ -1,5 +1,8 @@
 'use strict'
 
+// eslint-disable-next-line
+const STR_ESCAPE = /[\u0000-\u001f\u0022\u005c\ud800-\udfff]|[\ud800-\udbff](?![\udc00-\udfff])|(?:[^\ud800-\udbff]|^)[\udc00-\udfff]/
+
 module.exports = class Serializer {
   constructor (options = {}) {
     switch (options.rounding) {
@@ -94,6 +97,11 @@ module.exports = class Serializer {
       str = str.toString()
     }
 
+    // Fast escape chars check
+    if (!STR_ESCAPE.test(str)) {
+      return quotes + str + quotes
+    }
+
     if (str.length < 42) {
       return this.asStringSmall(str)
     } else {