const a = [q, w, e, r, y, u, i, o, p] a.length=9
const b = [0, 1, 2, 3, 4, 5, 6, 7, 8 ]
<script> const length = 9; const ar = Array.from({length}, (_, i) => i); document.write(JSON.stringify(ar, "", " ")); </script>
const a = ['q', 'w', 'e', 'r', 'y', 'u', 'i', 'o', 'p']; let b = a.map((e, i) => i) alert(b)