wp ajax route to increment post view count

functions.php

<?php

function get_post_count($id = null) {
  if($id == null) return;

  $key = 'post_views_count';
  $count = get_post_meta($id, $key, true);
  if($count == '') {
    $count = 0;
    delete_post_meta($id, $key);
    add_post_meta($id, $key, $count);
  }

  return $count;
}

function set_post_count($id = null, $count = 0) {
  if($id == null) return;

  $key = 'post_views_count';
  $count = get_post_count($id);
  $count++;
  update_post_meta($id, $key, $count);
}

function adaptable_post_view_increase( WP_REST_Request $request ) {  
  $id = (int) $request['id'];
  set_post_count($id);

  return;
}

add_action('rest_api_init', function () {

  register_rest_route( 'adaptable', '/view/(?P<id>\d+)', array(
      'methods' => 'POST',
      'callback' => 'adaptable_post_view_increase',
  ));

});