ReDoS check

[mbtools]

Feature

Coming back to #600 (which was 8 years ago)... Nowadays, there are excellent libraries available to check a regex against ReDoS vulnerabilities. I suggest adding such check to regex101. For example, recheck could be used to validate the entered regex and return a "safe" or "vulnerable" badge which is shown above the regex.

Examples

Safe regex:

Evil regex:

Evil regex showing complexity as well:

Suggestion

The check does take some time (as one can see in the playground) so it probably should be an option that is off by default.

[firasdib]

That looks interesting, thanks for sharing! The backend dependency will require some additional work load management, but perhaps it could be an on demand button click?

[mbtools]

sure, a button would work as well

[firasdib]

Just noticed this library only supports basic regex syntax. That's very unfortunate...

[mbtools]

too, bad. https://www.npmjs.com/package/redos-detector is the other one I know of. it takes an AST from a parser as input.