const { registerCheckoutFilters } = window.wc.blocksCheckout; // Adjust cart item class of the order summary items. registerCheckoutFilters( 'example-extension', { cartItemClass: ( value, extensions, args ) => { // Return early since this filter is not being applied in the Summary context. // We must return the original value we received here. if ( args?.context !== 'summary' ) { return value; } return 'my-custom-class'; } } );