Would be nice if it could also handle punctuation, but I guess that might be a breaking change:

Str::splitWords('foo, bar, baz.') === ['foo', 'bar', 'baz'];

Thanks for your pull request to Laravel!

Unfortunately, I'm going to delay merging this code for now. To preserve our ability to adequately maintain the framework, we need to be very careful regarding the amount of code we include.

If applicable, please consider releasing your code as a package so that the community can still take advantage of your contributions!

Str::splitWords('foo, bar, baz.')

That would be possible with this change:

-       return mb_split('\s+', $value);
+       return array_filter(mb_split('\W+', $value));