Array flatten

array-flatten

/*
  Flatten an array of arbitrarily nested arrays of integers into a flat array of integers
  [[1,2,[3]],4] -> [1,2,3,4]
  <object Array> arrayFlatten(<object Array>);
*/
function arrayFlatten ( ary, ret ) {
    ret = ret === undefined ? [] : ret;
    for (var i = 0; i < ary.length; i++) {
        if (Array.isArray(ary[i])) {
            arrayFlatten(ary[i], ret);
        } else {
            ret.push(ary[i]);
        }
    }
    return ret;
}