WooCommerce - Add meta to cart, checkout and order

<?php
  // show the custom meta data on the cart and checkout pages
  add_filter( 'woocommerce_get_item_data', 'tp_get_custom_item_data', 10, 2 );
  function tp_get_custom_item_data( $item_data, $cart_item ) {
    if( isset( $cart_item['size'] ) ) {
      $item_data[] = array( 'name' => 'Size', 'value' => $cart_item['size'] );
    }
    return $item_data;
  }

  // add custom meta to order
  // nb action 'woocommerce_add_order_item_meta' is deprecated
  add_action( 'woocommerce_new_order_item', 'tp_add_custom_meta_to_order', 99, 3 );
  function tp_add_custom_meta_to_order( $item_id, $item, $order_id ) {
    if( isset( $item->legacy_values['size'] ) ) {
      wc_add_order_item_meta( $item_id, 'Size', $item->legacy_values['size'] );
    }
  } // end function