Add multiple products to cart in the URL in WooCommerce

wc_multiple_products_to_cart.php

<?php
add_action( 'wp_loaded', 'maybeAddMultipleProductToCart', 25 );

/**
 * Add Multiple products by URL
 * @example
 *  simple:     http://wpplugins.local/cart/?add-to-cart=27,28
 *  variation : http://wpplugins.local/cart/?add-to-cart=208,32
 * @return void
 * @throws Exception
 */
function maybeAddMultipleProductToCart(): void {
	
	// Early return
	if ( ! function_exists('WC') || empty( $_REQUEST['add-to-cart'] ) || ! str_contains( $_REQUEST['add-to-cart'], ',' ) ) {
		return;
	}
	
	$productIDs = array_filter( array_map( 'absint', explode( ',', $_REQUEST['add-to-cart'] ) ) );
	
	// Early return
	if ( empty( $productIDs ) ) {
		return;
	}
	
	$added = [];
	foreach ( $productIDs as $productID ) {
		$product = wc_get_product( $productID );
		
		if ( $product && $product->is_type( 'variable' ) ) {
			wc_add_notice(
				sprintf(
					__(
						'Please choose product options by visiting <a href="%1$s" title="%2$s">%2$s</a>.',
						'woocommerce'
					),
					esc_url( get_permalink( $productID ) ),
					esc_html( $product->get_name() ) ),
				'error'
			);
			continue;
		}
		
		if ( false !== WC()->cart->add_to_cart( $productID ) ) {
			$added[ $productID ] = 1;
		}
	}
	
	if ( ! empty( $added ) ) {
		wc_add_to_cart_message( $added, true );
	}
}