Sales tax not updated when shipping option is changed if buyer pays with Credit/Debit rather than PayPal? - paypal

Question

In the PayPal JavaScript SDK when the order is created the client passes the shipping cost options. If the purchaser changes the shipping option from within the PayPal window, the sales tax must be recalculated because sales tax applies to shipping for this product. The sales tax is not passed in the order creation but the onShippingChange event is fired/invoked after the address is first applied in PayPal; and then the new values, including sales tax, are passed through return actions.order.patch().
If the purchaser pays through clicking the PayPal button, all works fine because the onShippingChange event is fired/invoked when the shipping option is changed. However, when the purchaser uses the Credit/Debit button to pay, the onShippingChange event is fired/invoked only once and not again when the shipping option is changed. If the user changes the shipping option, the cost appears to be taken from the data passed in the order creation and since the onShippingEvent is not run again, the sales tax remains based upon the initial shipping option.
The only difference in these two scenarios is which button the purchaser uses to pay: either PayPal for an account, or Credit/Debit to pay as a guest. All the JS code is the same.
Am I doing something wrong that is causing the onShippingChange event code to not be invoked? Thank you.
A couple things I've noticed while working on this. One is that the messages of "contacting merchant" and "processing" vary, such that when the shipping option is changed when paying with credit/debit, the message is only "processing". When paying with PayPal the message is "contacting merchant." Another is that even after the values are updated, with the sales tax inaccurate, the total cost shown in the top right corner of the PayPal window differs from the total in larger font in the message by difference in shipping options. The one in large font never changes when the shipping option is changed.
In the image below, the shipping option was changed from $9.25 priority to $4.00 standard. The initial total was $28.83. When shipping was changed to standard, the cost changed as $(28.83-9.25+4.00) = $23.58. Sales tax was not adjusted; and it should be $23.27.
I asked a similar question a day or so ago, but thought the values were correct in both payment scenarios but now see they are not.
Update:
After messing around with various options it occurred to me that I don't need to provide shipping options in the PayPal window. If the buyer wants to change the option, he'll have to cancel and change the order in the web page. That eliminates the issue of onShippingChange not firing. Not ideal; but good enough for our little case, especially since few buyers will be changing their shipping option in PayPal, for they see all that cost info. before clicking a payment button.
paypal.Buttons({
// Sets up the transaction when a payment button is clicked
createOrder: function(data, actions) {
return actions.order.create({
purchase_units: [{
reference_id: "HardCopy_0001",
amount: {
value: order.discSub.toFixed(2)
},
shipping: {
options: [
{
id: "STD",
label: "USPS Standard",
type: "SHIPPING",
selected: order.el_shipOptsInp[0].checked,
amount: {
value: order.shipStdVal.toFixed(2),
currency_code: "USD"
}
},
{
id: "PRI",
label: "USPS Priority",
type: "SHIPPING",
selected: order.el_shipOptsInp[1].checked,
amount: {
value: order.shipPriVal.toFixed(2),
currency_code: "USD"
}
}
]
}
}],
});
},
// Finalize the transaction after payer approval
onApprove: function(data, actions) {
return actions.order.capture().then(function(orderData) {
/* ... */
});
},
onShippingChange: function (data, actions) {
try {
// Reject non-US addresses
if (data.shipping_address.country_code !== 'US') {
return actions.reject();
}
const taxRate = data.shipping_address.state === 'PA' ? order.taxRate : 0,
shippingAmount = parseFloat(data.selected_shipping_option.amount.value),
tax_total = taxRate === 0 ? 0 : Math.round( (order.discSub + shippingAmount) * order.taxRate * 100)/100,
oTotal = order.discSub + shippingAmount + tax_total;
if ( data.selected_shipping_option.id === "STD" ) {
if ( !order.el_shipOptsInp[0].checked ) {
order.el_shipOptsInp[0].checked = true;
order.change();
}
} else if ( !order.el_shipOptsInp[1].checked ) {
order.el_shipOptsInp[1].checked = true;
order.change();
}
return actions.order.patch([{
op: "replace",
//path: "/purchase_units/#reference_id==\'default\'/amount",
path: "/purchase_units/#reference_id=='HardCopy_0001'/amount",
value: {
value: oTotal.toFixed(2),
currency_code: "USD",
breakdown: {
item_total: {
currency_code: "USD",
value: order.discSub.toFixed(2)
},
shipping: {
currency_code: "USD",
value: shippingAmount.toFixed(2)
},
tax_total: {
currency_code: "USD",
value: tax_total.toFixed(2)
}
}
}
}
]);
} catch (err) {
console.log("We apologize. There was an error in the onShippingChange event. Reason is provided below.");
console.log(err);
order.error();
return actions.reject();
}
},
onError: function(err) {
console.log(err);
// For example, redirect to a specific error page
//window.location.href = "/your-error-page-here";
order.error();
}
}).render('#paypal-button-container');