Enqueue a JavaScript file in a custom Wordpress plugin

custom-api-route-4.php

function custom_route_enqueue_scripts() {
    wp_enqueue_script('custom-route-script', plugin_dir_url(__FILE__) . 'custom-route-script.js', array(), '1.0', true);
}

add_action('wp_enqueue_scripts', 'custom_route_enqueue_scripts');