Redirect to shop if cart is emptied on cart page in WooCommerce 3+

In WooCommerce I want to redirect from cart to shop page when cart is empty and I am using this code:

function cart_empty_redirect_to_shop(){
    global $woocommerce;

    if ( is_page('cart') and !sizeof($woocommerce->cart->cart_contents) ) {
        wp_redirect( get_permalink( wc_get_page_id( 'shop' ) ) ); exit;
    }
}
add_action( 'wp_head', 'cart_empty_redirect_to_shop' );

This code works only if cart is empty and I try to go on cart page. But if I am already on cart page and I remove all cart items, I have to reload the page to get redirected. So I guess I have to add something in the code to reload the page. Any thoughts?

I would appreciate if anyone could help me with this.

Answer

Your code is a bit obsolete since WooCommerce version 3. Now on cart page, PHP redirect is useless, because Emptying cart is an Ajax customer live event. So in this case Javascript (jQuery) is required.

Use the following instead, that handle all cases:

add_action( 'template_redirect', 'empty_cart_redirection' );
function empty_cart_redirection(){
    if( is_cart() ) :
    
    // Here set the Url redirection
    $url_redirection = get_permalink( wc_get_page_id( 'shop' ) );
    
    // When trying to access cart page if cart is already empty  
    if( WC()->cart->is_empty() ){
        wp_safe_redirect( $url_redirection );
        exit();
    }
    
    // When emptying cart on cart page
    wc_enqueue_js( "jQuery(function($){
        $(document.body).on( 'wc_cart_emptied', function(){
            if ( $( '.woocommerce-cart-form' ).length === 0 ) {
                $(window.location).attr('href', '" . $url_redirection . "');
                return;
            }
        });
    });" );
    endif;
}

Code goes in functions.php file of the active child theme (or active theme). Tested and works in all WooCommerce versions since version 3.