checkout
  .onReady(() => setLoading(false))
  .onValidation(({ canSubmit }) => updatePageUi(canSubmit))
  .onPaymentResult((result) => {
    if (result.status === "succeeded") showSubmitted(result.paymentIntentId);
    if (result.status === "processing") showPending(result.paymentIntentId);
    if (result.status === "requires_payment_method") showError(result.error.message);
  })
  .onCheckoutError((error) => showCheckoutError(error.message));