<?php
function my_theme_enqueue_script()
{
  /* Enqueue local script */
  wp_enqueue_script( 'my-theme-scripts', get_template_directory_uri() . '/public/js/app.js', array(), '1.0.0', true );
}

add_action( 'wp_enqueue_scripts', 'my_theme_enqueue_script' );
?>