[taeric]

I did not realize we were debating HOF versus pure functions.

That is, I'm fine with using both the pure and HO functions. I just think hiding the HOF ones behind a normal function call is usually a big win for readability.

So, to do the full example:

    elements = [1,2,3,4]
    doubledElements = doubleElements(elements)
    function doubleElements(e) {
        function double(n) { return n*2; }
        return e.map(double);
    }

Where I would assume the "reader" code would only have the first two lines. The rest would be behind the implementation layer. If the double function would be used elsewhere, no need to scope it to doubleElements.