References

summary
public	F addProduct(id: number, title: string, price: number) adds a product to the products object
public	F formatAddress(customerEmail: string): address returns an customer address in a format appropriate for putting on an envelope
public	F productById(productId: number): Object takes a `productId` and returns the product corresponding to that id.
public	F productCost(productId: number): number takes a `productId` and returns the price of the product corresponding to that id.
public	F shopTitle(): string Returns the title of the shop
public	F totalCost(customerEmail: string, orderId: number): number returns the total cost of an order which is the sum of all products contained in an order
public	F updateProductPrice(id: number, newPrice: number) updates the price of a product in the products object
public	F upperCase(inputString: string) Coverts a string to uppercase
public	F upperCaseShopTitle(): string Returns the shop title in uppercase.
public	T address: Object An address
public	T customer: Object A customer
public	T item: Object An item which is part of an order
public	T order: Object An order
public	T product: Object A product