Search live Ajax Woocommerce - ajax

Question

It is necessary to reach the search entries instantly, but why can I cause such an error?
This error : POST https://localhost/theme/wp-admin/admin-ajax.php 500 (Internal Server Error)
Following my code:
HTML
<input type="text" name="keyword" id="keyword" onkeyup="fetch()"></input>
<div id="datafetch">Search results will appear here</div>
functions.php
add_action( 'wp_footer', 'ajax_fetch' );
function ajax_fetch() {
?>
<script type="text/javascript">
function fetch(){
jQuery.ajax({
url: '<?php echo admin_url('admin-ajax.php'); ?>',
type: 'post',
data: { action: 'data_fetch', keyword: jQuery('#keyword').val() },
success: function(data) {
jQuery('#datafetch').html( data );
console.log(data);
}
});
}
</script>
<?php }
add_action('wp_ajax_data_fetch' , 'data_fetch');
add_action('wp_ajax_nopriv_data_fetch','data_fetch');
function data_fetch(){
$tax_query[] = array(
'taxonomy' => 'product_visibility',
'field' => 'name',
'operator' => 'NOT'
);
$query = new WC_Product_Query(
array(
'tax_query' => $tax_query,
'posts_per_page' => -1,
's' => esc_attr( $_POST['keyword'] ),
'post_type' => 'post'
)
);
$products = $query->get_products();
if($products) {
foreach( $products as $product) {
echo '
'. $product->get_name() .' ';
}
}
wp_reset_postdata();
die();
}
i am getting an error like this
debug.log
Stack trace:
#0 C:\xampp\htdocs\theme\wp-includes\class-wp-hook.php(303): data_fetch('')
#1 C:\xampp\htdocs\theme\wp-includes\class-wp-hook.php(327): WP_Hook->apply_filters('', Array)
#2 C:\xampp\htdocs\theme\wp-includes\plugin.php(470): WP_Hook->do_action(Array)
#3 C:\xampp\htdocs\theme\wp-admin\admin-ajax.php(187): do_action('wp_ajax_data_fe...')
#4 {main}
Thank you advance