Conditionally Enqueue JS per Post Type

conditionally-enqueue-js.php

add_action( 'wp_enqueue_scripts', 'enqueue_cpt_script' );
function enqueue_cpt_script() {
  if ( 'cpt-type' === get_post_type() ) {
    if ( wp_script_is( 'file.js', 'enqueued' ) ) {
      return;
    } else {
      wp_register_script( 'file name', get_stylesheet_directory_uri() . '/js/file.js' );
      wp_enqueue_script( 'file name' );
    }
  }
}