This event is triggered when a user purchases an item and completes their order.
ImportantDue to the importance of the Purchase event, it's imperative that all of its attributes (Invoice, Customer, Product, Order) be correctly set.
- If Purchase event attributes are not entered correctly, the following error may be generated in your project's logs: 
"Unfortunately, event "Purchase" hasn't been tracked since you have provided a nullable parameter or a not valid one." orderId,goal,productsproperties are required to be non-empty.- The 
phoneshould be passed in the following format:(country code)(phone number)- Example phone format: 
13303332222 - If the phone is deemed not valid, the following warning log will be emitted: 
Unfortunately, event hasn't been tracked since you have provided a nullable parameter or a not valid one. 
 - Example phone format: 
 - If 
paymentMethodorcouponsproperties are not null, they must be non-empty. productId,skuIdproperties are required to be non-empty.price,quantityproperties are required to be greater than or equal to 0.amount,tax,shippingproperties are required to be greater than or equal to 0.0.- If 
totalDiscountproperty is not null, it must be greater than or equal to 0.0. 
Supported Currency Values
USD, KRW, AED, LTL, ARS, MAD, AUD, MXN, BGN, MYR, BOB, NOK, BRL, NZD, CAD, PEN, 
CHF, PHP, CLP, PKR, CNY, PLN, COP, RON, CZK, RSD, DKK, RUB, EGP, SAR, EUR, SEK, 
GBP, SGD, HKD, THB, HRK, TRY, HUF, TWD, IDR, UAH, ILS, VEF, INR, VND, JPY, ZAR
Implementation
val couponList = mutableListOf<String>()
couponList.add("TestCoupon")
val products = mutableListOf<Product>()
val product = Product(
    productId = String,
    skuId = String,
    price = Double,
    quantity = Long
)
products.add(product)
val invoice = Invoice(
    amount = Double,
    tax = Double,
    shipping = Double,
    totalDiscount = Double?,
    currency = Currency
)
val customer = Customer.createCustomer(
    customerEmail = String,
    customerPhone = Long
)
val order = Order(
    orderId = String,
    invoice = invoice,
    paymentMethod = String?,
    products = products,
    customer = customer,
    couponList = couponList,
    goal = String
)
Wunderkind.getInstance().trackPurchase(order)let invoice = Invoice(
    amount: Decimal,
    tax: Decimal,
    shipping: Decimal,
    totalDiscount: Decimal?,
    currency: Currency)
let customer = Customer(
    email: String,
    phone: String?)
let product = Product(
    productId: String,
    skuId: String,
    price: NSDecimalNumber,
    quantity: Int64)
let order = Order(orderId: "TestOrderId", invoice: invoice, paymentMethod: String?, products: [product], customer: customer, coupons: [String]?, goal: String)
Wunderkind.shared.trackPurchase(order: order)var customer = Customer.createCustomerWithPhone(
    email: String, 
    phone: Int
);
var invoice = Invoice(
    amount: double,
    shipping: double,
    currency: Currency,
    tax: double,
    totalDiscount: double?
);
var product = Product(skuId: String, price: double, quantity: int, productId: String);
var myOrder = Order(orderId: String, invoice, paymentMethod: String?, products, customer, couponList: List<String>?, goal: String)
Wunderkind().trackPurchase(myOrder);let product = new Product(
    skuId: string,
    price: number,
    quantity: number,
    productId: string
)
let customer = new Customer(string email, string phone)
let invoice = new Invoice(
    amount: number,
    shipping: number,
    currency: Currency,
    tax: number,
    totalDiscount?: number
)
let order = new Order(coupons?: string[]; orderId: string; invoice, customer, products: Product[], goal: string, paymentMethod?: string);
Wunderkind.trackPurchase(order);