[hmsimha]

I'd go with `Math.max(...arr)` personally. Math.max is a variadic function, no need to add a reduce into the mix.

[roryokane]

That implicitly calls Function.prototype.apply(), which will fail if given more arguments than an implementation-specific limit (https://stackoverflow.com/questions/22747068/is-there-a-max-...). Looping with reduce() avoids that restriction.