JS Константы

constant.js

var constant = (function() {
    var
        constants = {}
        , ownProp = Object.prototype.hasOwnProperty
        , allowed = {
            string: 1
            , number: 1
            , boolean: 1
        }
        , prefix = (Math.random() + '_').slice(2)
    ;
    
    return {
        set: function(name, value) {
            if(this.isDefined(name)) {
                return false;
            }
            
            if(!ownProp.call(allowed, typeof value)) {
                return false;
            }
            
            constants[prefix + name] = value;
            return value;
        }
        , isDefined: function(name) {
            return ownProp.call(constants, prefix + name);
        }
        , get: function(name) {
            if(this.isDefined(name)) {
                return constants[prefix + name];
            }
            
            return null;
        }
    }
})()