Get all product terms and attributes (API rest)

product-terms.php

<?php

/**
* Get all product terms and attributes
*
*/
function get_all_product_terms() {
	global $wpdb;
	$taxonomies = $wpdb->get_results( "SELECT attribute_id, attribute_name, attribute_label FROM wp_woocommerce_attribute_taxonomies" );

	$data = array();

	foreach ($taxonomies as $tax){
		$terms = get_terms( "pa_" . $tax->attribute_name );
		
		foreach ($terms as $term){
			$data[] = array(
				'term_id' =>  $term->term_id,
				'term_name' => $term->name,
				'term_slug' => $term->slug,
				'attribute_id' => $tax->attribute_id,
				'attribute_name' => $tax->attribute_label,
				'attribute_slug' => $tax->attribute_name
			);
		}

	}

	return $data;
}

add_action('rest_api_init', function() {
    register_rest_route('wp/v1', 'product_terms', [
        'methods' => 'GET',
        'callback' => 'get_all_product_terms',
    ]);
});