The :+1: emoji is not recognized

[mislav]

This is because the [\w\.]+ regex doesn't allow a literal + character.

I suggest the following regex: :([\w+-]+):

[mislav]

For the same reason, it's not safe to use the emoji ID to generate a classname like this gh-emoji-${id} because emojis can contain + and - characters.

[rpunkfu]

Thanks @mislav! :) I'm working on fix and tests for our new regex to avoid this type of bugs in future :)
Regarding your second comment, I proposed that we move emojis names from class tag. :)

[zzarcon]

Fixed on v0.2.4, more info #18. Thanks for the help @mislav ^^