var checkoutParams = { lineItems: [{ price: price, quantity: 1 }], mode: mode, successUrl: 'https://www.example.com/checkout?result=success', cancelUrl: 'https://www.example.com/checkout/?result=cancel' } if (window.Rewardful && window.Rewardful.referral) { checkoutParams.clientReferenceId = window.Rewardful.referral; } stripe.redirectToCheckout(checkoutParams);