A loader file use to load array data returned by PHP files within a directory (EG: configuration data)

Loader.php

<?php

class Loader
{
  /** @var array $cache */
  protected static array $cache = [];

  /** @var string $path */
  protected static string $path = __DIR__ . '/../path/to/directory/where/files/are/located';

  /**
   * Get a config value using dot notation:
   *
   * EG: "database.hostname"
   */
  public static function get(string $key, mixed $default = null): mixed
  {
    [$file, $path] = self::splitKey($key);

    $config = self::loadFile($file);

    // Walk through nested keys (like hostname inside database)
    foreach ($path as $segment) {
      if (!is_array($config) || !array_key_exists($segment, $config)) {
        return $default;
      }
      $config = $config[$segment];
    }

    return $config;
  }

  /**
   * Load an entire config file, with caching.
   */
  public static function load(string $file): array
  {
    return self::loadFile($file);
  }

  /**
   * Internal: load the config file and cache it.
   */
  protected static function loadFile(string $file): array
  {
    if (!isset(self::$cache[$file])) {
      $path = self::$path . '/' . $file . '.php';

      if (!file_exists($path)) {
        throw new Config\ConfigFileNotFound("Config file '$file' not found at '$path'");
      }

      self::$cache[$file] = include $path;
    }

    return self::$cache[$file];
  }

  /**
   * Split "database.hostname" into ["database", ["hostname"]]
   */
  protected static function splitKey(string $key): array
  {
    $parts = explode('.', $key);
    $file = array_shift($parts);

    return [$file, $parts];
  }
}