JavaScriptで列挙型みたいなもの。

enum.js

(function () {
  var slice = [].slice;

  var Enum = function () {
    var args = slice.call(arguments);

    var count, len;
    var result = {};

    for (count = 0, len = args.length; count < len; count += 1) {
      result[args[count]] = count;
    }

    return result;
  };

  this.Enum = Enum;
}).call(this);