Invalid regex group (reverse lookahead) in Firefox

Question

I have a rather confusing regex expression to match words and punctuation within a sentence:

var sentence = "Exclamation! Question? Full stop. Ellipsis...";
var words = sentence.toLowerCase().match(/\w+(?:'\w+)*|(?<![!?.])[!?.]/g);
console.log(words);

In Chrome, this outputs:

[ "exclamation", "!", "question", "?", "full", "stop", ".", "ellipsis", "." ]

In Firefox, this expression causes an error which seems to be due to the reverse lookahead.

I was wondering if it would be possible to rewrite this expression in a way which will work in Firefox, or if there is any other way in which I could accomplish this?

Answer 1

You can use a positive lookahead instead

\w+(?:'\w+)*|[!?.](?![!?.])

var sentence = "Exclamation! Question? Full stop. Ellipsis...";
var words = sentence.toLowerCase().match(/\w+(?:'\w+)*|[!?.](?![!?.])/g);
console.log(words);