I've read Adding stylesheets (CSS) and JavaScript (JS) to a Drupal 8 module and I can see where you can add assets that are part of your module or from a CDN or external source. What about if that library you want to add is already a core asset?

I'm trying to add jquery.ui.accordion to my modules so in my *.libraries.yml I have:

    /core/assets/vendor/jquery.ui/ui/widgets/accordion-min.js: { minified: true }
    - core/jquery.ui
    - core/jquery.ui.widget

That library is never loaded. What am I missing? Is there a better way to add core assets to my module?

EDIT: I've also tried different paths like:

core/assets/vendor/jquery.ui/ui/widgets/accordion-min.js: { minified: true }
../../../core/assets/vendor/jquery.ui/ui/widgets/accordion-min.js: { minified: true }
  • I’m not sure your approach is right here
    – Kevin
    Commented Feb 14, 2019 at 21:23
  • I'd agree with that. I switched it up to my answer below and that seems to work for me for now. I've been working with Drupal 8 for less than a month and Drupal itself for less than a year.
    – frmt
    Commented Feb 14, 2019 at 21:45

1 Answer 1


I just scraped the MY_MODULE.libraries.yml and utilized one of the other methods of adding assets, by:

function MY_MODULE_page_attachments(array &$attachments) {
  $attachments['#attached']['library'][] = "core/jquery.ui.accordion";
  //new addition below
  $attachments['#attached']['library'][] = "MY_MODULE/MY_MODULE.accordion";

This works for me. Perhaps you don't need a MY_MODULE.libraries.yml if you are trying to add libraries that already exist in core.

Edit: So I still have a MY_MODULE.libraries.yml file however it now just adds my module's javascript (with a dependency to jQuery). It's just some Javascript that initializes jQuery UI accordions. I still use the code above to add jQuery s UI accordion javascript and my own.

  • If the library is already defined by core, you don't redefine it in your module, you just add it to #attached as you did in the line $attachments['#attached']['library'][] = "core/jquery.ui.accordion";
    – Jaypan
    Commented Feb 15, 2019 at 2:49

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