Get a JS console and try this
^ This regex '.' will match the single character 'a'.
Now try with a complex unicode char like an emoji:/./.exec('😂')
The JS regex matches half of the unicode character.
What is interesting is if you specify a 2 letter match JS finds the character:
In other unrelated regex bugs: \w can not understand accents:/\w/.exec('Ä')
People are upset about Python's handling of unicode too.