See it live on GitHub Pages or at js-challenges.surge.sh.
I created this back in 2017 to provide some very basic JavaScript drills for my students. The original version has a suite of features around login, user management, tracking student progress, and instructors adding their own custom code challenges; however, all of this was disabled when I stopped keeping up the hosting of the back end and database.
It uses Angular 1.8 and Karma and Jasmine for unit tests.