random.js 746 Bytes
'use strict';

/* global crypto:true */
var crypto = require('crypto');

// This string has length 32, a power of 2, so the modulus doesn't introduce a
// bias.
var _randomStringChars = 'abcdefghijklmnopqrstuvwxyz012345';
module.exports = {
  string: function(length) {
    var max = _randomStringChars.length;
    var bytes = crypto.randomBytes(length);
    var ret = [];
    for (var i = 0; i < length; i++) {
      ret.push(_randomStringChars.substr(bytes[i] % max, 1));
    }
    return ret.join('');
  }

, number: function(max) {
    return Math.floor(Math.random() * max);
  }

, numberString: function(max) {
    var t = ('' + (max - 1)).length;
    var p = new Array(t + 1).join('0');
    return (p + this.number(max)).slice(-t);
  }
};