The modifiers read-only property of the PaymentRequestEvent interface returns an array of PaymentDetailsModifier objects containing modifiers for payment details.

An array of PaymentDetailsModifier objects containing modifiers for payment details. These objects contain the following properties:

supportedMethods

A payment method identifier. The members of the PaymentDetailsModifier object only apply to the payment if the user selects this payment method.

total

A PaymentItem object containing the following properties:

label

A string containing a human-readable description of the item, which may be displayed to the user.

amount

A PaymentCurrencyAmount object (see total > Value).

pending

A boolean. When set to true it means that the amount member is not final. This is commonly used to show items such as shipping or tax amounts that depend upon selection of shipping address or shipping option.

additionalDisplayItems

An array of PaymentItem objects providing additional display items to be included in the payment details. This member is commonly used to add a discount or surcharge line item indicating the reason for the different total amount for the selected payment method that the user agent MAY display.

data

An object that provides optional information that might be needed by the supported payment methods. If supplied, it will be JSON-serialized.

• Web-based payment apps overview
• Setting up a payment method
• Life of a payment transaction
• Using the Payment Request API
• Payment processing concepts