UUID v4 generation

readme.md

Not the smallest footprint out there, but it seems to be faster when I compare against other solutions, but not when I use jsperf.com for some reason. This solution is based upon that gist by the way. Biggest difference is that this is more readable...

This will generate a version 4 UUID. The non-packed version passes JSLint. Performance comparison at jsperf.

Reduced footprint.

uuid-recursive.js

/*jslint indent: 2 */
(function (global) {
  'use strict';
  global.uuid = (function () {
    var that = {},
      internal = {};

    that.create = function () {
      var result = '';
      result = internal.recursiveCreator(result);
      return result;
    };

    internal.recursiveCreator = function (result) {
      if (result.length === 36) {
        return result;
      }
      result += internal.addHexadecimalOrDash(result.length);
      return internal.recursiveCreator(result);
    };

    internal.addHexadecimalOrDash = function (index) {
      if (internal.shouldAddDash(index)) {
        return '-';
      }
      return internal.randomHexadecimal(index);
    };

    internal.shouldAddDash = function (index) {
      return index === 8 || index === 13 || index === 18 || index === 23;
    };

    internal.randomHexadecimal = function (index) {
      var random;
      if (index === 14) {
        // Required for version 4 of UUID
        return '4';
      }
      random = internal.randomNumber(index);
      return random.toString(16);
    };

    internal.randomNumber = function (index) {
      if (index === 19) {
        // Required for version 4 of UUID
        return Math.floor(Math.random() * 4) + 8;
      }
      return Math.floor(Math.random() * 16);
    };

    return that.create;
  }());
}(this));

uuid-recursive.min.js

(function(d){'use strict';d.uuid=(function(){var c={},internal={};c.create=function(){var a='';a=internal.recursiveCreator(a);return a};internal.recursiveCreator=function(a){if(a.length===36){return a}a+=internal.addHexadecimalOrDash(a.length);return internal.recursiveCreator(a)};internal.addHexadecimalOrDash=function(a){if(internal.shouldAddDash(a)){return'-'}return internal.randomHexadecimal(a)};internal.shouldAddDash=function(a){return a===8||a===13||a===18||a===23};internal.randomHexadecimal=function(a){var b;if(a===14){return'4'}b=internal.randomNumber(a);return b.toString(16)};internal.randomNumber=function(a){if(a===19){return Math.floor(Math.random()*4)+8}return Math.floor(Math.random()*16)};return c.create}())}(this));

uuid-red.js

(function (exports) {
    'use strict';

    var random = function (multiplier) {
            return Math.floor(Math.random() * multiplier);
        },

        hexadecimal = function (index) {
            return ((index === 19) ? random(4) + 8 : random(16)).toString(16);
        },

        nexttoken = function (index) {
            if (index === 8 || index === 13 || index === 18 || index === 23) {
                return '-';
            }

            if (index === 14) {
                return '4';
            }

            return hexadecimal(index);
        },

        generate = function () {
            var index, uuid = '';

            while ((index = uuid.length) < 36) {
                uuid += nexttoken(index);
            }

            return uuid;
        };

    exports.generate = generate;

}(typeof exports === 'undefined' ? this.uuid = {} : exports));

uuid-red.min.js

(function(a){"use strict";var b=function(a){return Math.floor(Math.random()*a)},c=function(a){return(19===a?b(4)+8:b(16)).toString(16)},d=function(a){return 8===a||13===a||18===a||23===a?"-":14===a?"4":c(a)},e=function(){for(var a,b="";36>(a=b.length);)b+=d(a);return b};a.generate=e})("undefined"==typeof exports?this.uuid={}:exports);

uuid.js

/*jslint indent: 2 */
(function (global) {
  'use strict';
  global.uuid = (function () {
    var that = {},
      internal = {};

    that.create = function () {
      var i,
        result = '';
      for (i = 0; i < 36; i += 1) {
        result += internal.addHexadecimalOrDash(i);
      }
      return result;
    };

    internal.addHexadecimalOrDash = function (index) {
      if (internal.shouldAddDash(index)) {
        return '-';
      }
      return internal.randomHexadecimal(index);
    };

    internal.shouldAddDash = function (index) {
      return index === 8 || index === 13 || index === 18 || index === 23;
    };

    internal.randomHexadecimal = function (index) {
      var random;
      if (index === 14) {
        // Required for version 4 of UUID (random)
        return '4';
      }
      random = internal.randomNumber(index);
      return random.toString(16);
    };

    internal.randomNumber = function (index) {
      if (index === 19) {
        // Required for version 4 of UUID (random)
        return Math.floor(Math.random() * 4) + 8;
      }
      return Math.floor(Math.random() * 16);
    };

    return that.create;
  }());
}(this));

uuid.min.js

(function(d){'use strict';d.uuid=(function(){var c={},internal={};c.create=function(){var i,result='';for(i=0;i<36;i+=1){result+=internal.addHexadecimalOrDash(i)}return result};internal.addHexadecimalOrDash=function(a){if(internal.shouldAddDash(a)){return'-'}return internal.randomHexadecimal(a)};internal.shouldAddDash=function(a){return a===8||a===13||a===18||a===23};internal.randomHexadecimal=function(a){var b;if(a===14){return'4'}b=internal.randomNumber(a);return random.toString(16)};internal.randomNumber=function(a){if(a===19){return Math.floor(Math.random()*4)+8}return Math.floor(Math.random()*16)};return c.create}())}(this));