onSubmit
In this method you should make a network call to the /payments endpoint of the Checkout API through your server.
We provide a PaymentComponentState which contains information about the state of the payment component at the moment the user submits the payment.
We also provide inside PaymentComponentState.data the parameters that we can infer from the component's configuration and the user input, especially the state.data.paymentMethod object with the shopper input details.
Use PaymentComponentData.SERIALIZER to serialize this data to a JSONObject. The rest of the /payments call request data should be filled in, on your server, according to your needs.
See https://docs.adyen.com/api-explorer/ for more information on the API documentation.
Parameters
The state of the payment component at the moment the user submits the payment.