Javascript 5 Module Pattern internal name
Because of the scoping inside a closure you will not run into a problem.

The Revealing Module Pattern

I want to introduce this type of module pattern because it does not need the helper object module. Instead of collecting all public functions inside an object called module return directly an object with all public functions. This will reduce code and result in a better to reading code.

var module = function () {
    var config = {
        css: {
            classes: {
                heading: 'h1',
                navbar: 'nav-bar'
            },
            ids: {
                widget: 'widget',
                block: 'block'
            }
        },
        userName: 'user',
        token: 'UUID'
    };

    function _moduleMethod() {
        console.log(config.userName);
    }

    function init() {
        _moduleMethod();
    }

    // Return an object as public API
    return {
        init: init  
    }
}();