For the record: the valid chars string is 62 characters, so naively using a modulo on a random byte will technically introduce a bias (since dividing 256 values by 62 leaves a remainder). I don't expect it to really matter here, but since you're putting in the effort of using crypto.randomBytes I figured you might appreciate the nitpick ;).
Melissa E. O'Neill has a nice article explaining what the problem is, and includes a large number of ways to remove the bias as well:
(in this case adding two more characters to the validChars string would be the easiest and most efficient fix, but I'm not sure if that is a possibility here)
For the record: the valid chars string is 62 characters, so naively using a modulo on a random byte will technically introduce a bias (since dividing 256 values by 62 leaves a remainder). I don't expect it to really matter here, but since you're putting in the effort of using crypto.randomBytes I figured you might appreciate the nitpick ;).
Melissa E. O'Neill has a nice article explaining what the problem is, and includes a large number of ways to remove the bias as well:
https://www.pcg-random.org/posts/bounded-rands.html
(in this case adding two more characters to the validChars string would be the easiest and most efficient fix, but I'm not sure if that is a possibility here)