I've experienced a similar drawback as of late—wanting to contribute but not entirely sure of my skills. I think a viable solution for this would be to use JS meetups in your area as an opportunity to start your own open-source project. The group could be relatively small, and the bi-monthly or monthly meetups paired with a Slack channel could get the project off the ground easily. Your first missteps or issues could then be played out in a small, controlled environment.

As an aside, a useful resource I've found is the guidelines set forth on this Scotch.io tutorial by Noman Ur Rehman: scotch.io/tutorials/contributing-to-open-source-s…

https://github.com/lhorie/mithril.js Beautiful MVC framework. Lightweight, extremely fast.

bountysource is a good source for chasing issues in open source projects and you can earn some money too.

There are many of open source projects around the world and people usually contribute to what they love or use at work. Because of that it is hard to answer what are good projects exactly for you.

You can take a look on my tiny vanilla library https://bunnyjs.com - the idea is described on first screen and it says everything you need to know. I am always opened for any suggestions, ideas, feedback but real help of course is unreplacable.

You can also add me on Twitter or Facebook /mevrael and I will tell you some very interesting other vanilla JS projects.

Http://aurelia.io

I would say check out the top trending repos on github here: https://github.com/trending/javascript . But to be honest, the best JavaScript early stage open source project you could contribute to is the one you create yourself to get learning. Build, learn, then you can get a perspective on other projects.