Generating strings from regular expression in JavaScript

Question

I think it can be done by generating strings using brute force and then try to match them to the supplied regex and printing if match.

But is there a better way to do this?

Regex are used to test if a string matches a pattern. I am aware of that. I thought it would be interesting to do it the way around.

Higher Order Perl has a section discussing this problem. It's worth reading for other reasons, too. — Dave Newton
– Dave Newton, Commented Feb 4, 2014 at 14:40
What's the problem you're trying to solve, what's the question? — David Thomas
– David Thomas, Commented Feb 4, 2014 at 14:40
There's no built-in way to generate matching strings from a regular expression in JavaScript. You'd have to write code to do it, and there are definitely better ways to do it than to generate random strings and see whether they match. It's a non-trivial problem however. — Pointy
– Pointy, Commented Feb 4, 2014 at 14:41
Possible duplicate of Generate a random string based on a regular expression — Sjoerd
– Sjoerd, Commented Apr 12, 2017 at 18:59

Philipp Gayret · Accepted Answer · 2014-02-04 14:43:42Z

16

If you're using JavaScript, there's Randexp which generates random strings that match a given regex.

Releases for browser

answered Feb 4, 2014 at 14:43

Philipp Gayret

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1 Comment

Anderson Green Over a year ago

Randexp generates only one random string from a regex. To generate every possible match, you can use genexp.js instead.

Sapnesh Naik · Accepted Answer · 2023-11-16 17:52:36Z

5

Use randexp.js to generate random strings from a regular expression:

console.log(new RandExp(/^([a-zA-Z]){5}([0-9]){4}([a-zA-Z]){1}$/).gen());
console.log(new RandExp(/^[0-9]{4}$/).gen());
console.log(new RandExp(/^[0-9,A-Z]{4}$/).gen());
console.log(new RandExp(/^([A-Z]){5}([0-9]){4}([A-Z]){1}$/).gen());

<script src="https://github.com/fent/randexp.js/releases/download/v0.4.3/randexp.min.js"></script>

edited Nov 16, 2023 at 17:52

answered Feb 27, 2020 at 18:20

Sapnesh Naik

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