Automatically add the product's size as a size attribute from different product fields for this product. [datafeedr][dfrpswc]

add_size_attribute-02.php

<?php

/**
 * Add the product's size as a size attribute for this product.
 *
 * The attribute "Size" with a slug of "size"
 * must already exist here:
 * WordPress Admin Area > Products > Attributes.
 *
 * @param array|string $value The current value of the $attribute for this $post.
 * @param string $attribute The slug of the attribute. Examples: pa_size or pa_shoe-size
 * @param array $post An array of post data including ID, post_title, post_status, etc...
 * @param array $product An array of product data returned from the Datafeedr API.
 * @param array $set A post array for this Product Set with an array key of postmeta containing all post meta data.
 * @param string $action The action the Product Set is performing. Value are either "insert" or "update".
 *
 * @return array|string The updated attribute's value.
 */
add_filter( 'dfrpswc_filter_attribute_value', function ( $value, $attribute, $post, $product, $set, $action ) {

	if ( $attribute !== 'pa_size' ) {
		return $value;
	}

	if ( isset( $product['size'] ) ) {
		return $product['size'];
	}

	if ( isset( $product['custom1'] ) ) {
		return $product['custom1'];
	}

	return $value;

}, 20, 6 );