window.shop.init();
window.shop.cart.get();
window.shop.cart.set();
window.shop.cart.clear();

// in my cart.js namespace file
export {get} from './get';

// in my shop.js
import * as cart from './cart';

global.shop = {
    cart
}

module shop {
    export const cart = {...}
}

(<any>window).shop = shop;

namespace shop {
    // ...
}

(<any>window).shop = shop;