var answer =

it should be:

var question =

one word. ROFL.

/bb|.*/s and /(bb|[^b]{2})/ aren’t equivalent my friend =)

No kidding. That’s why I posted my implementation. Anything other than “bb” (including the empty string) is not “bb”. Therefore I read my regex as “two Bs or anything other than two Bs”, while I read the original as “two Bs or any two non-Bs, captured to group one”. I read your regexes here as “over-engineered, inefficient patterns that simply match any position or any two, non-line break characters.” Mine can alternatively be read as “match either ‘bb’ or the first line of the subject string.”

Any single-character string is matched by yours but not the original. Also any two-character string containing only one b. In fact, yours will match anything including an empty string.

It’s funny to see Azat came up with essentially the same answer I did =) Except one half of his alternation consumes while the other half doesn’t – which might be his intention, but it’s more likely you’d want both sides of the alternation to consume, or neither side to consume. That’s why I prefer /(?=bb)|(?!bb)/ (non-consuming) or /(?:(?=bb)|(?!bb))../.

This last one can be reduced to /.{2}/, but that doesn’t read quite as well =)