JavaScript "range" helper: Generates an iterable list of numbers from `start` to `end`, inclusive.

range.js

export default function range(_start, _end) {
  // If only one argument (n) is passed, we generate a range from 0 to n.
  const start = typeof _end === 'undefined' ? 0 : _start;
  const end = typeof _end === 'undefined' ? _start : _end;

  // "direction" multiplier to produce a decreasing sequence if `start` is greater than `end`.
  const direction = start > end ? -1 : 1;

  const size = Math.abs(end - start) + 1;

  return Array.from({ length: size }, (_, idx) => start + (idx * direction));
}