Function range

code/solutions/04_1_the_sum_of_a_range.js:1–10

(start, end, step = start < end ? 1 : -1)

function range(start, end, step = start < end ? 1 : -1) {
  let array = [];

  if (step > 0) {
    for (let i = start; i <= end; i += step) array.push(i);
  } else {
    for (let i = start; i >= end; i += step) array.push(i);
  }
  return array;
}

function sum(array) {
  let total = 0;