This is the robbers' post. The cops' is here.
Your challenge is to take a cop's post and find an input that the regex matches but the program returns a falsey value.
Once you have cracked a cop's post, comment in a link to your crack. (If you don't have enough rep to comment, please say so, and someone will do it for you.) The robber with the most cracks wins.
Let's say a cop's regex is (all of the flavors):
And the program is (JS):
Than a valid crack would be
0, because the regex matches
0 is falsey.