I have a recently upgraded Symfony 3 to 4 project in which I have been using yarn to manage my js dependencies.

I decided to try installing webpack-encore using the following commands:

 composer require symfony/webpack-encore-pack
 yarn install

I noticed my package.json was not altered and thought it might happen later, so I continued on.
I configured webpack.config.js and tried running

 yarn encore dev --watch

I got an error which I did not record at the time saying something to the effect that encore command could not be found.

I decided I wasn't ready to troubleshoot the problem and uninstalled with the following command:

 composer remove symfony/webpack-encore-pack

After which my pre-existing package.json had been removed.

I would expect the installation to give a warning or error if it cannot handle a pre-existing package.json.

Also I definitely do not think that it should be presumed that the package.json is there only because of webpack-encore and it should remain after webpack-encore has been removed.

Thanks