We have 4 types of components in Magento 2, as I have been using three of them, but my question is how to use const LIBRARY = 'library'; component.

As name implies, this is something to include third party libraries, but any one can give me an example on how to include a library and use the lib in global application level.

* Different types of components
const MODULE = 'module';
const LIBRARY = 'library';
const THEME = 'theme';
const LANGUAGE = 'language';

I did not find any information about const LIBRARY = 'library'; in the official Magento 2 documentation Register your component.

4 Answers 4


I'm not sure why it's not documented on the official documentation but here's how it should be done from what I understand:

So it's very similar to the way your register modules, you just need to create lib/internal/Your/Library/registration.php with the following content:



Also you can find the right location is properly documented here: http://devdocs.magento.com/guides/v2.0/architecture/archi_perspectives/components/modules/mod_conventions.html

To use/load these libraries you follow the same way as it's done with the Magento\Framework library. So using :

use Your\Library\Custom\Class;

You can find the core registration.php under lib/internal/Magento/Framework folder

  • Thanks @Raphael, Can please give me an example on how to use/load these libraries added "LIBRARY = 'library" in third-party/custom implementations. Mar 8, 2017 at 12:35
  • Am looking forward to have basic example on how to use this in real time. Mar 8, 2017 at 12:36
  • @Krishati95Dev see my updated answer Mar 8, 2017 at 12:41

You can refer from core file's where it is been used .Here is the example this may help you , You need to give name which you want to include :-

ComponentRegistrar::register(ComponentRegistrar::LIBRARY, '', DIR);

Example :

    __DIR__ );

I could get the answer https://magento.stackexchange.com/a/163418/36759 to work, but only after declaring namespaces inside the classes in the library, so keep that in mind.


From Magento 2.2 the described half-documented library approach does not work anymore. Magento encourages developers to add libraries using composer according to:


What works would be adding your own autoloader: lib/internal/Your/Library/registration.php

namespace Your\Library;

spl_autoload_register(function ($class) {
  $prefix   = __NAMESPACE__ . '\\';
  $base_dir = __DIR__.'/';
  $len = strlen($prefix);

  if (strncmp($prefix, $class, $len) !== 0) {
  $relative_class = substr($class, $len);
  $file = $base_dir . str_replace('\\', '/', $relative_class) . '.php';
  if (file_exists($file)) {
    require $file;

This works due to app/etc/NonComposerComponentRegistration.php which still includes the following directories:

$pathList[] = dirname(dirname(__DIR__)) . '/lib/internal/*/*/registration.php';
$pathList[] = dirname(dirname(__DIR__)) . '/lib/internal/*/*/*/registration.php';

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