PaymentRequest: show() method
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
The PaymentRequest
interface's
show()
method instructs the user agent to begin the
process of showing and handling the user interface for the payment request to the
user.
Only one payment request can be in the process of being handled at once, across all
documents. Once one PaymentRequest
's show()
method has been
called, any other call to show()
will by rejected with an
AbortError
until the returned promise has been concluded, either by being
fulfilled with a PaymentResponse
indicating the results of the payment
request, or by being rejected with an error.
Note: In reality, despite the fact that the specification says this can't be done, some browsers, including Firefox, support multiple active payment requests at a time.
If your architecture doesn't necessarily have all of the data ready to go at the moment
it instantiates the payment interface by calling show()
, specify the
detailsPromise
parameter, providing a Promise
that is
fulfilled once the data is ready. If this is provided, show()
will not
allow the user to interact with the payment interface until the promise is fulfilled, so
that data can be updated prior to the user engaging with the payment process.
Processing the result and, if necessary, calling PaymentResponse.retry()
to retry a failed payment can all be done either asynchronously or synchronously,
depending on your needs. For the best user experience, asynchronous solutions are
typically the best way to go. Most examples on MDN and elsewhere use
async
/await
to wait asynchronously while results are validated and so forth.
Syntax
js
show()
show(detailsPromise)
Parameters
detailsPromise
Optional-
An optional
Promise
that you can provide if your architecture requires that the payment request's details need to be updated between instantiating the payment interface and the user beginning to interact with it. The promise should resolve with an object containing the updated information:displayItems
Optional-
An array of objects, each describing one line item for the payment request. These represent the line items on a receipt or invoice, each with the following properties:
amount
-
An object describing the monetary value of the item. This object includes the following fields:
currency
-
A string containing a valid 3-letter ISO 4217 currency identifier (ISO 4217) indicating the currency used for the payment
value
. value
-
A string containing a valid decimal value representing the mount of currency constituting the payment amount. This string must only contain an optional leading "-" to indicate a negative value, then one or more digits from 0 to 9, and an optional decimal point (".", regardless of locale) followed by at least one more digit. No whitespace is permitted.
label
-
A string specifying a human-readable name or description of the item or service being charged for. This may be displayed to the user by the user agent, depending on the design of the interface.
pending
-
A Boolean value which is
true
if the specifiedamount
has not yet been finalized. This can be used to show items such as shipping or tax amounts that depend upon the selection of shipping address, shipping option, or so forth. The user agent may show this information but is not required to do so.
error
Optional Deprecated-
A string specifying an error message to present to the user*.* When calling
updateWith()
, includingerror
in the updated data causes the user agent to display the text as a general error message. For address field specific errors, useshippingAddressErrors
. modifiers
Optional-
An array of
PaymentDetailsModifier
objects, each describing a modifier for particular payment method identifiers. For example, you can use one to adjust the total payment amount based on the selected payment method ("5% cash discount!"). shippingAddressErrors
Optional Deprecated-
An
AddressErrors
object which includes an error message for each property of the shipping address that could not be validated. shippingOptions
Optional-
An array of
PaymentShippingOption
objects, each describing one available shipping option from which the user may choose. total
Optional-
An object with the same properties as the objects in
displayItems
providing an updated total for the payment. Make sure this equals the sum of all of the items indisplayItems
. This is not calculated automatically. You must update this value yourself anytime the total amount due changes. This lets you have flexibility for how to handle things like tax, discounts, and other adjustments to the total price charged.
Return value
A Promise
that eventually resolves with a PaymentResponse
.
The promise is resolved when the user accepts the payment request (such as by clicking a
"Pay" button in the browser's payment sheet).
Exceptions
Exceptions are not thrown but returned when the Promise
rejects.
AbortError
DOMException
-
Returned if the user agent is already showing a payment panel. Only one payment panel may be visible at a time across all documents loaded by the user agent.
The promise is also rejected with
AbortError
if the user cancels the payment request. InvalidStateError
DOMException
-
Returned if the same payment has already been shown for this request (its state is
interactive
because it is being shown already). NotSupportedError
DOMException
-
Returned if the user agent does not support the payment methods specified when the
PaymentRequest
constructor was called. SecurityError
DOMException
-
Returned if the call to
show()
was not in response to a user action, such as aclick
orkeyup
event. Other reasons aSecurityError
may be thrown are at the discretion of the user agent, and may include situations such as too many calls toshow()
being made in a short time orshow()
being called while payment requests are blocked by parental controls.
Security
Transient user activation is required. The user has to interact with the page or a UI element in order for this feature to work.
Usage notes
async/await syntax
Using await
to wait for a promise to be resolved makes it possible to
write the code to handle payments particularly cleanly:
js
async function processPayment() {
try {
const payRequest = new PaymentRequest(methodData, details, options);
payRequest.onshippingaddresschange = (ev) =>
ev.updateWith(checkAddress(payRequest));
payRequest.onshippingoptionchange = (ev) =>
ev.updateWith(checkShipping(payRequest));
const response = await payRequest.show();
await validateResponse(response);
} catch (err) {
/* handle the error; AbortError usually means a user cancellation */
}
}
In this code, the methods checkAddress()
and checkShipping()
,
respectively, check the shipping address and the shipping option changes and supply in
response either an object or a promise to return one;
this object contains the fields in the PaymentResponse
which have been or
need to be changed.
The validateResponse()
method, below, is called once show()
returns, in order to look at the returned response
and either submit the
payment or reject the payment as failed:
js
async function validateResponse(response) {
try {
if (await checkAllValues(response)) {
await response.complete("success");
} else {
await response.complete("fail");
}
} catch (err) {
await response.complete("fail");
}
}
Here, a custom function called checkAllValues()
looks at each value in the
response
and ensures that they're valid, returning true
if
every field is valid or false
if any are not. If and only if every field is
valid, the complete()
method is called on the
response with the string "success"
, which indicates that everything is
valid and that the payment can complete accordingly.
If any fields have unacceptable values, or if an exception is thrown by the previous
code, complete()
is called with the string "fail"
, which
indicates that the payment process is complete and failed.
Instead of immediately failing, you could choose to call
retry()
on the response object to ask the user
agent to try to process the payment again; this should usually only be done after the
user has made any needed corrections to the order.
Starting the payment process, in the end, is as simple as calling the
processPayment()
method.
then/catch syntax
You can also use the older promise-based approach to work with payments, using the
then()
and catch()
functions on the promise returned by show()
:
js
function processPayment() {
const payRequest = new PaymentRequest(methodData, details, options);
payRequest.onshippingaddresschange = (ev) =>
ev.updateWith(checkAddress(payRequest));
payRequest.onshippingoptionchange = (ev) =>
ev.updateWith(checkShipping(payRequest));
payRequest
.show()
.then((response) => validateResponse(response))
.catch((err) => handleError(err));
}
This is functionally equivalent to the processPayment()
method using the
await
syntax.
js
function validateResponse(response) {
checkAllValues(response)
.then((response) => response.complete("success"))
.catch((response) => response.complete("fail"));
}
You could even have checkAllValues()
be a synchronous function, although
that may have performance implications you don't want to deal with:
js
function validateResponse(response) {
if (checkAllValues(response)) {
response.complete("success");
} else {
response.complete("fail");
}
}
See the article Using promises for more information if you need more information about working with promises.
Examples
In the following example, a PaymentRequest
object is instantiated before
the show()
method is called. This method triggers the user agent's built-in
process for retrieving payment information from the user. The show()
method
returns a Promise
that resolves to a PaymentResponse
object
when the user interaction is complete. The developer then uses the information in
the PaymentResponse
object to format and send payment data to the server.
You should send the payment information to the server asynchronously so that the final
call to paymentResponse.complete()
can indicate the success or failure of
the payment.
js
button.onclick = async function handlePurchase() {
// Initialization of PaymentRequest arguments are excerpted for the sake of
// brevity.
const payment = new PaymentRequest(methods, details, options);
try {
const response = await payment.show();
// Process response here, including sending payment instrument
// (e.g., credit card) information to the server.
// paymentResponse.methodName contains the selected payment method
// paymentResponse.details contains a payment method specific response
await response.complete("success");
} catch (err) {
console.error("Uh oh, something bad happened", err.message);
}
};
The following example shows how to update the payment sheet as it's being presented to the end-user.
js
async function requestPayment() {
// We start with AU$0 as the total.
const initialDetails = {
total: {
label: "Total",
amount: { value: "0", currency: "AUD" },
},
};
const request = new PaymentRequest(methods, initialDetails, options);
// Check if the user supports the `methods`
if (!(await request.canMakePayment())) {
return; // no, so use a web form instead.
}
// Let's update the total as the sheet is shown
const updatedDetails = {
total: {
label: "Total",
amount: { value: "20", currency: "AUD" },
},
};
const response = await request.show(updatedDetails);
// Check response, etc.
}
document.getElementById("buyButton").onclick = requestPayment;
Specifications
Specification |
---|
Payment Request API 1.1 # dom-paymentrequest-show |
Browser compatibility
BCD tables only load in the browser