WC Advanced Fees - custom subtotal

wc-advanced-fees-custom-subtotal.php

<?php


function custom_wcaf_fee_amount_subtotal( $subtotal ) {

	$subtotal = 0;
	$category_id = '61'; // Your category ID here.

	$cart_items = WC()->cart->get_cart();
	foreach ( $cart_items as $key => $item ) {
		if ( has_term( $category_id, 'product_cat', $item['product_id'] ) ) {
			$subtotal += $item['line_subtotal'] + $item['line_subtotal_tax'];
		}
	}

	return $subtotal;

}
add_filter( 'woocommerce_advanced_fees_get_fee_amount_subtotal', 'custom_wcaf_fee_amount_subtotal' );