PRs and contributions are welcome! However, before creating a pull request, please take a look at the Github issues and open a new issue if your issue isn't found. It's good to validate what you want to do first, before spending time on writing the PR.
To develop on react-calendar-heatmap, a good way to start is to run the demo site. See the demo README for instructions on how to run the demo.
Keep CI tests passing by running yarn test and yarn run lint often.
When creating a PR, you should run yarn run format and commit any formatting changes, to ensure that source files are consistently formatted with Prettier.