Extend macros list of JetEngine listing.

jet-engine-wc-product-query-sale-products-macros.php

<?php
	add_filter( 'jet-engine/listings/macros-list', '__your_theme_prefix_get_products_on_sale' );

	// Add macros to list.
	function __your_theme_prefix_get_products_on_sale( $macros_list ) {

		$macros_list['on_sale_products_ids'] = [
			'label' => esc_html__( 'On Sale Products IDs', 'jet-engine' ),
			'cb'    => 'get_on_sale_products_ids',
		];

		return $macros_list;

	}

	// Macros callback handle.
	function get_on_sale_products_ids() {
		return array_merge( array( 0 ), wc_get_product_ids_on_sale() );
	}