add_action( 'pre_get_posts', 'njengah_hide_out_of_stock_products' );

function njengah_hide_out_of_stock_products( $query ) {

  if ( ! $query->is_main_query() || is_admin() ) {
    return;
  }

     if ( $outofstock_term = get_term_by( 'name', 'outofstock', 'product_visibility' ) ) {

     $tax_query = (array) $query->get('tax_query');

      $tax_query[] = array(
      'taxonomy' => 'product_visibility',
      'field' => 'term_taxonomy_id',
      'terms' => array( $outofstock_term->term_taxonomy_id ),
      'operator' => 'NOT IN'
   );

  $query->set( 'tax_query', $tax_query );

}

  remove_action( 'pre_get_posts', 'njengah_hide_out_of_stock_products' );

}