List post from current taxonomy children

I had an idea of combining the first code with this solution that lists posts from a specifik taxomony:

<?php $terms = get_terms('productcategories');
    foreach ($terms as $term) {
        $wpq = array (
        'taxonomy'=>'productcategories',
        'term'=>$term->slug,
        'order'=>'asc',
        'orderby'=>'title');
        $query = new WP_Query ($wpq);
        echo "$term->name:<br />"; 
        ?>
        <?php
        if ($query->have_posts() ) : while ($query->have_posts() ) : $query->the_post(); ?>
        <a href="https://wordpress.stackexchange.com/questions/123059/<?php the_permalink();?>"><?php the_title();?></a>, 
        <?php endwhile; endif; wp_reset_query(); ?>
        <?php
        echo "<br />";   
    }
?>

I managed to combine the two, so this is my current solution. Maybe not the best but it works.

<?php 
    $term_slug = get_query_var( 'term' );
    $taxonomyName = get_query_var( 'taxonomy' );
    $current_term = get_term_by( 'slug', $term_slug, $taxonomyName );
    $termchildren = get_term_children( $current_term->term_id, $taxonomyName );
    foreach ($termchildren as $child) {
    $term = get_term_by( 'id', $child, $taxonomyName );
        $wpq = array (
        'taxonomy'=>$taxonomyName,
        'term'=>$term->slug,
        'order'=>'asc',
        'orderby'=>'title');
        $query = new WP_Query ($wpq);
        echo "$term->name:<br />"; 
        ?>

        <?php
        if ($query->have_posts() ) : while ($query->have_posts() ) : $query->the_post(); ?>
        <a href="https://wordpress.stackexchange.com/questions/123059/<?php the_permalink();?>"><?php the_title();?></a>, 
        <?php endwhile; endif; wp_reset_query(); ?>
        <?php
        echo "<br />";   
    }
?>