POW Answer – Explain That SQL #1

To answer last week’s POW, the purpose of the SQL was to generate a random string of letters and numbers. I actually wrote two different JavaScript function that can produce the same results. The following is the slightly more straight-forward solution:

function randomChars(len) {
  for(var n, s = ""; --len;) {
    n = parseInt(Math.random() * 62);
    s = String.fromCharCode(n + (n < 26 ? 65 : n < 52 ? 71 : -4));
  }
  return s;
}

The next version is a bit harder to follow because it involves recursion:

function recRandomChars(len) {
  if(!len){ return ""; }
  var n = parseInt(Math.random() * 62);
  return recRandomChars(--len)
    + String.fromCharCode(n + (n < 26 ? 65 : n < 52 ? 71 : -4));
}

One practical application of this is to generate a password with random characters.