Hey!

I was reading your article when I came across this repo. Wanted to play a bit with the code.

I think it would be great if the README.md would link directly to a working CodeSandbox (or any other online-ide-tool) project so that cloning/installing/starting is not necessary.

CodeSandbox supports creating sandboxes directly from Github, here's the example I made: https://codesandbox.io/s/github/the-road-to-learn-react/react-interval-setstate-unmounted-component-performance

In order to create the sandbox click: "Create Sandbox" -> "Import from GitHub". See the pic.

Zrzut ekranu 2019年06月14日 15 59 19

If you were to create such sandbox from master as of now, CodeSandbox complains about .prettierrc but the fix is here: #7

Thanks!