Add Product Custom Field in Listing Returning WooCommerce Rest API

functions.php

<?php 

function wc_add_rest_line_items( $response, $post, $request ) {
	
	foreach( $response->data['line_items'] as $item_id => $line_item ) {
			if ( ! empty( $line_item['product_id'] ) ) {
				$product_id = ! empty( $line_item['variation_id'] ) ? $line_item['variation_id'] : $line_item['product_id'];
        $meta_key = 'Assigned Field Name';
        $meta_key_selected = 'Selected Field Name';
        
				$response->data['line_items'][ $item_id ][$meta_key] =  get_post_meta( $product_id,  $meta_key_selected, true );
			}
	}
	
	return $response;	
}

add_filter( 'woocommerce_rest_prepare_shop_order_object', 'wc_add_rest_line_items', 10, 3 );