Simple function to create API keys consisting of only lower case, upper case alphabets and numbers

createKey.js

function createKey(len) {
  var out = [], rand;
  len = len || 20;
  while(len > 0) {
    rand = Math.round(Math.random() * 123);
    if ((rand > 47 && rand < 58) || (rand > 64 && rand < 91) || (rand > 96 && rand < 123)) {
      out.push(rand);
      len--;
    }
  }
  return String.fromCharCode.apply(String, out);
}