range.js

/**
 * @template {number} T
 * @param {T} start 
 * @param {T} end 
 * @param {T | (old: T) => T} increase 
 * @returns {T[]}
 */
export default function range(start, end, increase = 1) {
  const increaser = typeof increase === 'function'
    ? increase
    : old => old + increase;

  const ret = [];
  for (let i = start; i < end; i = increaser(i)) {
    ret.push(i);
  }

  return ret;
}