Generates a random string and returns them or sends it to callback. Great for generating unique identifiers.

get-random-string.js

/*
Has two optional options parameters:
- length - 8 characters by default
- characters - upper- and lowercase characters and numbers by default
*/

function getRandomString(options, callback) {
  options = options || {};
  options.length = options.length || 8;
  options.characters = options.characters || '0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz';
  
  callback = callback || function () {};

  var result = '';
  while (options.length--) {
    result += options.characters.charAt(
      Math.floor(Math.random() * options.characters.length)
    );
  }
  
  callback(result);
  return result;
}

// EXAMPLES

// default use, e.g. "2a2giHof"
getRandomString();

// set length, e.g. "xBh"
getRandomString({
  length : 3
});

// set length and list of characters to use, e.g. "BAB"
getRandomString({
  length : 3,
  characters : 'ABC'
});