Something like this works in Ruby but not in Javascript:
str = "now is the time"
p str.gsub(/[a-z&&[^aeiou]]/, '*')
Notice the && on the second line.
[a-z&&[^aeiou]] works but if you remove the [] around the whole regex and have a-z&&[^aeiou] it won't work. Why? Is this unique to Ruby only? I haven't been able to find much info about this feature.