For a new Gutenberg block

extra.php

<?php
/**
*Plugin name: Extra
*Author: My name
*Version: 1.0.0
*/

function loadMyBlockFiles() {
	wp_enqueue_script(
		'my-test-text',
		plugin_dir_url(__FILE__). 'extra.js',
		array('wp-blocks', 'wp-i18n', 'wp-editor'),
		true
	);
}

add_action('enqueue_block_editor_assets', 'loadMyBlockFiles');
?>