My Drum Machine React App won't display in Codepen

I’m currently doing the Drum Machine React project in Codepen ( and after finishing up most of the React code the app will not display. The error that shows up in the console reads: [object Error] {}.

Could someone please take a look at my code and tell me where the problem lies. I’ve gone through the code myself line by line but can’t figure out what’s causing this issue.

So I got a console error from that react-dom import.

By replacing it with the following (codepen defaults) it works.

Thanks that solved it