Helper function for registering and enqueueing CSS and JavaScript files within a WordPress plugin or theme.

WPAssetLoader.php

/**
 * Helper function for registering and loading scripts and styles.
 * Uses regex to determine if the file is CSS or JavaScript and calls
 * the proper WordPress register and enqueue functions accordingly.
 *
 * @name	        ID to register with WordPress
 * @file_path		Path to actual file, relative to your plugin or theme, without preceding slash.
 * @for			Whether this is for a plugin or a theme.
 */
function load_file($name, $file_path, $for = 'plugin') {
  
  $file = trailingslashit(dirname(__FILE__)) . $file_path;
  
  if($for == 'plugin') {
    $url = plugins_url($file_path, dirname(__FILE__));
  } elseif($for == 'theme') {
    $url = trailingslashit(dirname(get_bloginfo('stylesheet_url))) . $file_path;
  }

  if(preg_match('/\.js(\.gz)?/', $file_path)) {
    $is_js = true;
  } elseif(preg_match('/\.css(\.gz)?/', $file_path)) {
    $is_css = true;
  } else {
    return false;
  }

  if(!file_exists($file)) {
    return false;
  } else {
    if($is_js) {
      wp_register_script($name, $url);
      wp_enqueue_script($name);
    } elseif($is_css) {
      wp_register_style($name, $url);
      wp_enqueue_style($name);
    }
  }

}