This is a small application that serves as a playground to test react-formule.
Run yarn link-local in react-formule, then run yarn link-local-lib and yarn install in formule-demo. To run the playground app, execute yarn dev and visit localhost:3030. You will see any changes in react-formule immediately in the playground app.
Another option (if you want to test the actual bundle, or if you want to link react-formule to a more complex application, which can be trickier) would be to use yalc. Run yarn build and yalc publish in react-formule, then run yalc add react-formule in formule-demo. If you make changes in react-formule and want to update formule-demo with those changes, run yarn build and yalc push in react-formule, and then yarn dev --force in formule-demo. Read the yalc docs for more info.
For more confort, you can also run yarn build:watch in react-formule, which will rebuild the bundle and push the changes to yalc automatically. For even more automation, you can use vite-plugin-restart in formule-demo (or in your own project using react-formule and Vite) and watch the bundle file inside of the .yalc folder, so that the Vite dev server is automatically reloaded once the new bundle is published. This advanced option is what we use to quickly test formule changes inside CAP.