RegExp.escape() in JavaScript

Have you ever tried to match a string like (a*) using a regular expression and got an unexpected result? That’s because certain characters in JavaScript regular expressions have special meaning. To treat them as normal characters, we need to escape them properly. Previously, developers had to manually escape those characters, but now the JavaScript community has added a new thing, which is RegExp.escape(), that will save time. In this blog, you will explore everything about regex escaping in JavaScript, why it matters, and how RegExp.escape() is used.

Table of Contents

• Meaning of Escape in Regular Expressions
• Manual Escaping
• RegExp.escape() (ES2025)
  • Example: Escaping Special Characters of Regular Expression in JavaScript
• Conclusion
• Escaping a Regular Expression in JavaScript – FAQs

Meaning of Escape in Regular Expressions

A regular expression is a sequence of characters that defines a search pattern. Regular expressions use certain characters as part of their pattern syntax. like ( . ) for matches any character, ( * ) means zero or more of the previous, and ( ^,$,+,?,(,),],[,},{, |, ) are all special characters. 

But what if you want to match them as plain characters in a string? Then, for doing this, you need to escape them using a backslash ( ). Let us understand this with the help of an example:

Example: Matching an exact string pattern (a*)

const text = "I am looking for (a*) pattern.";

const regex = /(a*)/;

console.log(regex.test(text));

Output:

Explanation: Let us say you want to match (a*) an exact string. But if you write like /(a*)/ and use the .test() method, then it cannot give you the expected output. Besides searching for the (a*) JavaScript, start searching for “”, “a”, “aa”, “aaa” – any number of a’s. Thus, if you want to produce a correct result, then you have to write like /(a*)/. So this will match only the exact string (a*).

Manual Escaping

Before RegExp.escape() came into the picture, developers had to write their own utility functions to escape special characters like this:

Syntax:

function escapeRegExp(string) {

  return string.replace(/[.*+?^${}()|[]\]/g, '\$&');

}

This works well for most cases but does not work for all. Thus, this is not a better way to escape a regular expression in JavaScript.

RegExp.escape() (ES2025)

The traditional way to escape special characters does not work well for every regular expression string. Thus, JavaScript comes with the solution for escaping strings in regular expressions.

The upcoming ECMAScript (ES2025) feature RegExp.escape() does exactly the same thing that we need. It takes a string and returns a regex-safe version that matches it. This method was initially proposed by Jordan Harband and others in earlier years and is expected to become a standard feature by 2025.

Since RegExp.escape() is part of ES2025, it may not be available in your JavaScript environment yet. Here’s a simple solution for this. Add this code to your code and start using RegExp.escape() today.

if (typeof RegExp.escape !== 'function') {

  RegExp.escape = function (string) {

    return String(string).replace(/[\^$.*+?()[]{}|]/g, '\$&');

  };

}

Let’s understand RegExp.escape() with the help of an example of escaping characters in regex. (. * + ? ^ $ { } ( ) | [ ] ) Some common regex-special characters that must be escaped.

Example: Escaping Special Characters of Regular Expression in JavaScript

Output:

Explanation: This example shows how to safely use a string containing special regex characters in a regular expression without those characters being misinterpreted as part of regex syntax. Here you can use the RegExp.escape() to handle escaping automatically.

Conclusion

Escaping a regular expression in JavaScript has always been a tricky task for the beginner developer, especially when working with user-generated input. The RegExp.escape() helps you a lot if you are tired of using backslashes or find it hard to read regex patterns. So next time if you’re building a search feature, processing user input, or constructing a regex, use RegExp.escape() for better results.

Escaping a Regular Expression in JavaScript – FAQs