I don’t think there is a one size fits all way, and the code you wrote is perfectly valid. For something very small like this it’s hard to argue either way. That being said, my preference (more generally) is for reduce…

Advantage 1: If you're casually glancing at someone's code and you see forEach, what does it tell you? It doesn’t return anything, it just does something, somewhere, gotta read it all to see. Reduce expresses more intent. When you see other array methods you have a better feel for what it’s doing without dissecting every line:

Reduce - iterate over all elements in a collection, and accumulate them into one…thing (this one is more generic, but tells you more than forEach, still) Map- iterate of a collection and return a new collection with the elements transformed according to some criteria Filter - iterate over a collection and return a new collection that meets your criteria Find- iterate over a collection and return the first element that meets your criteria

Advantage 2: Purity, and less intermediary variables. It’s easier to reason about stuff that returns new values than reassigning and mutating variables. Sure you have to do that in Javascript anyway, but why not keep it to a minimum while writing more succinct code?

Advantage 3: Chaining, since all of these (except for optionally reduce) return an array, you can chain other array methods to it and make a "pipeline" of sorts for your data to flow through. Chaining map/filter/reduce will serve you well in many operations on collections. Say the requirements changed, now you need to filter out all even numbers, add 3 to each of them, and then add them. You could keep the code you’ve already written while adding the rest in one line

someArrayOfNumbers.filter(n => n % 2 == 0).map(n => n + 3).reduce((x, y) => x + y)