Real JavaScript constants

config.js

var config = function() {

	/**
	 * Set a debug flag
	 * @type {boolean}
	 */
	var DEBUG = true;
	
	/**
	 * Set the environment variable
	 * @returns {string}
	 */
	var ENV = function() {
		switch (window.location.host) {
			case 'localhost':
			case 'staging.domain.com':
				return 'DEV';
			break;
			case 'domain.com':
				return 'PROD';
			break;
		}
		
		return false;
	};

	/**
	 * Getter for Constants
	 * 
	 * So we can't access Constants directly and therefore they can't 
	 * be overwritten.
	 * 
	 * @param constant {String} - variable reference to the Constant
	 */
	var get = function getConstant(constant) {
		return $.isFunction(constant) ? constant() : constant;
	};

	return {
		DEBUG: get(DEBUG),
		ENV: get(ENV)

	};

}();


console.log(config.ENV);