Regex fails only on Safari

Question

I have the following simple email validation regex: /(.+){2,}@(.+){2,}\.(.+){2,}/

This works fine on Firefox, Chrome etc, but fails on Safari.

Why would this perfectly valid regex fail on Safari? I could not find elements in the regex that are not supported by Safari.

/(.+){2,}@(.+){2,}\.(.+){2,}/.test('123@abc.nl');

Above fails on Safari, but not on any other browser.

The regex is just bad, you should never quantify `(.+)` like that. It should be written as `/.{2,}@.{2,}\..{2,}/` — Wiktor Stribiżew, Mar 05 '21 at 12:10
Be that as it may, the behavior should not be inconsistent between Safari and other browsers, right? — ViBoNaCci, Mar 05 '21 at 12:18
No, different regex engines have different tolerance wrt the catastrophic backtracking prone patterns. — Wiktor Stribiżew, Mar 05 '21 at 12:32

score 2 · Accepted Answer · answered Mar 05 '21 at 13:29

Different regex engines have different tolerance to catastrophic backtracking prone patterns.

Yours is a catastrophic backtracking prone pattern as you quantify (.+) with the {2,} quantifier that makes (.+) match two or more times (that is, match one or more times twice or more, which makes it fail very slowly with non-matching patterns.)

If you meant to match any two or more chars, quantify the . pattern and not a .+ one:

/.{2,}@.{2,}\..{2,}/

Or, use existing email validation patterns..

Regex fails only on Safari

1 Answers1