A short snippet of JS code

unnamed.js

function f(arr) {
    if (arr.length < 10) {
        var acc = 0;
        for (var i=0; i<arr.length; ++i) {
            acc += arr[i];
        }
        return [acc / arr.length];
    } else {
        var acc = 0;
        var ret = [];
        for (var i=0; i<10; ++i) {
            acc += arr[i];
        }
        ret[0] = acc / 10;
        for (var i=10; i<arr.length; ++i) {
            acc = acc - arr[i-10] + arr[i];
            ret[i-9] = acc / 10;
        }
        return ret;
    }
}