All the JS libraries included as part of the CERN Clean theme are now (more) compliant with Drupal 8 themes JS best practices and standards.
Current code can be checked working live on https://test-ogomezal.web.cern.ch/
So far some bugs were fixed and no new bugs have been introduced that I know of.
Feel free to merge this if you think it's worth it!
NOTE: SCSS & PHP files are not changed, it's only the code formatting
Regards, Óscar