random-string/lib/random-string.js

Simple Module for generating Random Strings

/*
 * random-string
 * https://github.com/valiton/node-random-string
 *
 * Copyright (c) 2013 Valiton GmbH, Bastian 'hereandnow' Behrens
 * Licensed under the MIT license.
 */

'use strict';

var numbers = '0123456789',
    letters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz',
    specials = '!$%^&*()_+|~-=`{}[]:;<>?,./';


function _defaults (opts) {
  opts || (opts = {});
  return {
    length: opts.length || 8,
    numeric: typeof opts.numeric === 'boolean' ? opts.numeric : true,
    letters: typeof opts.letters === 'boolean' ? opts.letters : true,
    special: typeof opts.special === 'boolean' ? opts.special : false,
    exclude: Array.isArray(opts.exclude)       ? opts.exclude : []
  };
}

function _buildChars (opts) {
  var chars = '';
  if (opts.numeric) { chars += numbers; }
  if (opts.letters) { chars += letters; }
  if (opts.special) { chars += specials; }
  for (var i = 0; i <= opts.exclude.length; i++){
    chars = chars.replace(opts.exclude[i], "");
  }
  return chars;
}

module.exports = function randomString(opts) {
  opts = _defaults(opts);
  var i, rn,
      rnd = '',
      len = opts.length,
      exclude = opts.exclude,
      randomChars = _buildChars(opts);
  for (i = 1; i <= len; i++) {
    rnd += randomChars.substring(rn = Math.floor(Math.random() * randomChars.length), rn + 1);
  }
  return rnd;
};