This project was generated using Angular CLI version 21.2.7.

It reproduce a bug where setting rootDir option in tsconfig.json break HMR when using ng serve. Just start the developpement server, open a browser on localhost:4200 and change the line in app.html. Observe nothing changes.

Remove the rootDir line in tsconfig.json and try again. The HMR should work with no problem.

To start a local development server, run:

ng serve

Once the server is running, open your browser and navigate to http://localhost:4200/. The application will automatically reload whenever you modify any of the source files.