JS: Range Function for Array 📜

There's no builtin range function to create a array.

This is the best function for generating an array. Most efficient and fastest, functional style, and without hack.

/*
xah_range(min, max) → return a array from min to max, inclusive.
xah_range(min, max, step) → in increment of step.
If step is not integer, then max may not be included.
http://xahlee.info/js/js_range_array.html
Version: 2019-10-31
*/

const xah_range = (
  min,
  max,
  step = 1,
) => (Array(Math.floor((max - min) / step) + 1).fill(min).map((
  x,
  i,
) => (x + i * step)));

// a simple range function
console.log(
  Array.from((Array(4)).keys()),
);
// [ 0, 1, 2, 3 ]