autoloader.php

<?php
namespace ElementorBeta;

if ( ! defined( 'ABSPATH' ) ) {
	exit; // Exit if accessed directly.
}

class Autoloader {
	/**
	 * Run autoloader.
	 */
	public static function run() {
		spl_autoload_register( [ __CLASS__, 'autoload' ] );
	}

	/**
	 * Autoload.
	 *
	 * For a given class, check if it exist and load it.
	 *
	 * @param $class
	 */
	private static function autoload( $class ) {
		if ( ! class_exists( $class ) ) {
			self::load_class( $class );
		}
	}

	/**
	 * Load class.
	 *
	 * For a given class name, require the class file.
	 *
	 * @param $relative_class_name
	 */
	private static function load_class( $relative_class_name ) {
		$relative_class_name = str_replace( ELEMENTOR_BETA_NAMESPACE . '\\', '', $relative_class_name );

		$filename = strtolower(
			preg_replace(
				[ '/([a-z])([A-Z])/', '/_/', '/\\\/' ],
				[ '$1-$2', '-', DIRECTORY_SEPARATOR ],
				$relative_class_name
			)
		);

		$filename = ELEMENTOR_BETA_DIR . $filename . '.php';

		if ( is_readable( $filename ) ) {
			require_once $filename;
		}
	}
}