Wordpress Template Redirect

template-first-child.php

<?php

/* In a filenamed template-first-child.php */

/*
Template Name: Go to first child
*/
?>


<?php 

/* In functions.php */

function redirect_template() {
  if (get_page_template_slug() == 'template-first-child.php') {
    global $post;
    $pagekids = get_pages("child_of=".$post->ID."&sort_column=menu_order");
    wp_redirect(get_permalink($pagekids[0]->ID));
    exit();
  }

}
add_action( 'pre_base_load', 'redirect_template', 100 );

?>

<?php

/* At the top of the base.php template */

use Roots\Sage\Setup;
use Roots\Sage\Wrapper;
do_action( 'pre_base_load' );

?>