Customize / Modify WooCommerce REST API response using filter

curl https://example.com/wp-json/wc/v3/customers/<user_id> \
	-u consumer_key:consumer_secret

add_filter('woocommerce_rest_prepare_customer', 'filter_response', 10, 3);
function filter_response($response, $user_data, $request){
	// Customize response data here
	$user_id = $user_data->ID;
	
	$response->data["custom"] = 3;
	return $response;
}

curl https://example.com/wp-json/wc/v3/products/<product_id> \
	-u consumer_key:consumer_secret

add_filter('woocommerce_rest_prepare_product_object', 'filter_product_response', 10, 3);
function filter_product_response($response, $post, $request){
	// Customize response data here
	$product_id = $post->get_id();
	
	$response->data["custom"] = 12;
	return $response;
}

curl https://example.com/wp-json/wc/v3/orders/<order_id> \
	-u consumer_key:consumer_secret

add_filter('woocommerce_rest_prepare_shop_order_object', 'filter_order_response', 10, 3);
function filter_($response, $post, $request){
    // Customize response data here
    $order_id = $post->get_id();

    $response->data["custom"] = 12;
    return $response;
}