refactor: use built-in wellformed operation (#774)

Author: climba03003

lib/serializer.js

@@ -1,8 +1,5 @@
 'use strict'
 
-// eslint-disable-next-line
-const STR_ESCAPE = /[\u0000-\u001f\u0022\u005c\ud800-\udfff]/
-
 module.exports = class Serializer {
   constructor (options) {
     switch (options && options.rounding) {
@@ -117,7 +114,7 @@ module.exports = class Serializer {
         }
       }
       return (last === -1 && ('"' + str + '"')) || ('"' + result + str.slice(last) + '"')
-    } else if (len < 5000 && STR_ESCAPE.test(str) === false) {
+    } else if (len < 5000 && str.isWellFormed()) {
       // Only use the regular expression for shorter input. The overhead is otherwise too much.
       return '"' + str + '"'
     } else {