Regex to find and replace emoji names within colons

Question

I'm trying to write a regex (for JavaScript's regex engine) that I can use to do a find and replace in text for emoji names within colons. Like in Slack or Discord when you type :smiley-face: and it replaces it when you submit the chat. I'm targeting text nodes only so I don't need to worry about other html inside the text.

Is it possible to write a regex that could match all of the following rules? (text highlighted with monospace blocks = regex positive matches)

:any-non-whitespace:
:text1:sample2:
:@(1@#$@SD: :s:
:nospace::inbetween: because there are 2 colons in the middle
:nospace:middle:nospace:

I'm starting with something like this but it's incomplete

/:(?!:)\S+:/gim

I'm trying to think of all the special cases that might possibly occur doing this. Maybe I'm overthinking it.

There's a lot of Twitch emotes involved so I can't use emoji unicode characters. The regex will find matches and replace with tags

Answer 1

I suggest using

:[^:\s]*(?:::[^:\s]*)*:

See the regex demo. It is the same pattern as :(?:[^:\s]|::)*:, but a bit more efficient because the (?:..|...)* part is unrolled.

Details

• : - a colon
• [^:\s]* - 0+ chars other than : and whitespace
• (?: - start of a quantified non-capturing group:
  • :: - double colon
  • [^:\s]* - 0+ chars other than : and whitespace
• )* - end of grouping, repeated 0 or more times (due to the * quantifier)
• : - a colon.

Answer 2

Do you want something like this regex?

(:(?![\n])[()#$@-\w]+:)

Demo,,, in which you can additionally insert unallowed characters into the character class of the (?![\n]) and also additonally insert allowed characters into the character class [()#$@-\w]