I decided to work on the ExpressJS Session project because it was something that I have used countless times as a backend developer. This issue related to this contribution was https://github.com/expressjs/session/issues/607/. This issue is essentially a request to add Promise support to the sessionStore object.
The solution to this was particularly interesting as we had to maintain backwards compatibility with older Node versions (> 0.8.x).
Here is the current PR link: https://github.com/expressjs/session/pull/635. This the tests for this PR are passing, however the coverage and test scope need to be improved for some of the methods (reload & destroy).
I technically worked alone on this project. However, not without the help of our mentor for the ExpressJS project.
It was really awesome to be able to contribute to something that you use regularly. I have gained a new appreciation for Open-Source Projects and everyone who has contributed to them.