Both are usable, but I just don't understand why you'd choose the separate line style if you were starting a new codebase. I can't see the benefit of it, but that could also be me not having enough experience with the separate line style to see it's advantages.

On the other hand, having the brace on the next line means that the parent statement and the code in the braces are further from each other, also more lines in the source file is more scrolling in general. You can fit less lines of code on the same vertical screen height if you have a lot of nested blocks or just generally use a lot of blocks. Especially for things like many small functions or many if blocks, being able to fit a few more on your screen is really convenient IMO.

For Javascript it's () => { }. Lamba functions! Because at least it's more readable than Perl.