How to create RegExp object in JavaScript?

A regular expression is an object that describes a pattern of characters. The JavaScript RegExp class represents regular expressions, and both String and RegExp define methods that use regular expressions to perform powerful pattern-matching and search-and-replace functions on the text.

A regular expression could be defined with the RegExp () constructor, as follows −

var pattern = new RegExp(pattern, attributes);
or simply
var pattern = /pattern/attributes;

The following are the parameters −

  • pattern − A string that specifies the pattern of the regular expression or another regular expression.
  • attributes − An optional string containing any of the "g", "i", and "m" attributes that specify global, case-insensitive, and multiline matches, respectively.


You can try to run the following code to learn how to implement RegExp object in JavaScript −

      <title>JavaScript RegExp</title>
         var re = new RegExp( "string" );
         document.write("re.constructor is:" + re.constructor);

Updated on: 19-Jun-2020


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