My background is mostly frontend development and I'm always looking to learn more about C.S. fundamentals and how JS libraries can be practically used for app development. I find myself checking out the following from time to time:https://github.com/gothinkster/realworld
https://github.com/prakhar1989/awesome-courses/blob/master/README.md
https://github.com/jwasham/coding-interview-university
Any good gems out there you recommend?