const xxx = str =>
Array.from(
{ length: 1 + str.length * 9 },
(n, i) => i--
? (n = i / 9 | 0, i %= 9,
Array.from(str, (m, j) => j === n ? i + (i >= m) : m).join(''))
: str
);const xxx = str =>
[...str].reduce((acc, n, i, a) => {
for (let j = 0; j < 9; j++) {
a[i] = j + (j >= n);
acc.push(''.concat(...a));
}
a[i] = n;
return acc;
}, [ str ]);