I finally finished the drum machine challenge. I initially built it with React but it was getting really messy so I switched to using React-Redux and it made things much better.
Here it is: https://kyur-wd.github.io/drum_machine/
Source code: https://github.com/Kyur-wd/drum_machine
I would love to hear your feedback (I was a bit lazy with choosing my own sounds, so I used the same sounds from the example to focus on the programming part )!