trait DependencyTrait

trait DependencyTrait {
    
    /**
     * The object's dependencies.
     *
     * @var array
     */
    protected $dependencies = [];
    
    /**
     * Adds a dependency.
     *
     * @param string $type
     *   Type of dependency being added: 'module', 'theme', 'config', 'content'.
     * @param string $name
     *   If $type is 'module' or 'theme', the name of the module or theme. If
     *   $type is 'config' or 'content', the result of
     *   EntityInterface::getConfigDependencyName().
     *
     * @see \Drupal\Core\Entity\EntityInterface::getConfigDependencyName()
     *
     * @return $this
     */
    protected function addDependency($type, $name) {
        if (empty($this->dependencies[$type])) {
            $this->dependencies[$type] = [
                $name,
            ];
            if (count($this->dependencies) > 1) {
                // Ensure a consistent order of type keys.
                ksort($this->dependencies);
            }
        }
        elseif (!in_array($name, $this->dependencies[$type])) {
            $this->dependencies[$type][] = $name;
            // Ensure a consistent order of dependency names.
            sort($this->dependencies[$type], SORT_FLAG_CASE);
        }
        return $this;
    }
    
    /**
     * Adds multiple dependencies.
     *
     * @param array $dependencies
     *   An array of dependencies keyed by the type of dependency. One example:
     *   @code
     *   array(
     *     'module' => array(
     *       'node',
     *       'field',
     *       'image',
     *     ),
     *   );
     *   @endcode
     *
     * @see \Drupal\Core\Entity\DependencyTrait::addDependency
     */
    protected function addDependencies(array $dependencies) {
        foreach ($dependencies as $dependency_type => $list) {
            foreach ($list as $name) {
                $this->addDependency($dependency_type, $name);
            }
        }
    }

}