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JavaScript - RegExp toString Method

The toString() method in JavaScript is commonly used to retrieve a string representation of an object. When it comes to regular expressions (RegEx), the RegExp.toString() method retrieves a string that represents the regular expression.

In JavaScript, a string is a data type representing a sequence of characters. Which can consist of letters, numbers, symbols, words, or sentences.

Syntax

Following is the syntax of JavaScript RegExp.toString() method −

RegExp.toString()

Parameters

  • It does not accept any parameter.

Return value

This method returns a string representing the given object (or regular expression).

Examples

Example 1

In the following example, we are using the JavaScript RegExp.toString() method to retrieve a string representing this regular expression "[a-zA-Z]".

<html>
<head>
   <title>JavaScript RegExp.toString() Method</title>
</head>
<body>
   <script>
      const regex = new RegExp("^[a-zA-Z\\s]*$");
      document.write("The regex: ", regex);
      document.write("<br>Type of regex: ", typeof(regex));
      
      //lets convert to string
      const result = regex.toString();
      document.write("<br>String representing of this regex: ", result);
      document.write("<br>Type of result: ", typeof(result));
   </script>
</body>
</html>

Output

The above program returns a string representing of this regex as −

The regex: /^[a-zA-Z\s]*$/
Type of regex: object
String representing of this regex: /^[a-zA-Z\s]*$/
Type of result: string

Example 2

If the current regex object is empty, this method will return "/(?:)/".

The following is another example of the JavaScript RegExp.toString() method. We use this method to retrieve a string representing this empty regex ("").

<html>
<head>
   <title>JavaScript RegExp.toString() Method</title>
</head>
<body>
   <script>
      const regex = new RegExp("");
      document.write("The regex: ", regex);
      document.write("<br>Type of regex: ", typeof(regex));
      
      //lets convert to string
      const result = regex.toString();
      document.write("<br>String representing of this regex: ", result);
      document.write("<br>Type of result: ", typeof(result));
   </script>
</body>
</html>

Output

After executing the above program, it will return "/(?:)/".

The regex: /(?:)/
Type of regex: object
String representing of this regex: /(?:)/
Type of result: string
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