export defaultfunction(array, f) {
var s = 0,
n = array.length,
a,
i = -1;
if (f == null) {
while (++i < n) if (a = +array[i]) s += a; // Note: zero and null are equivalent.
}
else {
while (++i < n) if (a = +f(array[i], i, array)) s += a;
}
return s;
}