How to get suffix of filename in javascript quickly?

This question has been asked a couple of times here on SO, but most answers are simply slow. I need the fastest implementation possible since I execute this on million filenames in a list.

filename.split(".").pop();

The code above works but imagine a long filename, isn’t there a way to start from the right? Otherwise, i could imagine that this here is faster than the common answers:

filename.reverse().split(".", 1).reverse()

const filename = 'foo/bar/baz/my-file.js';
const extension = filename.slice(filename.lastIndexOf('.') + 1);
console.log(extension);