First of all, you need the SASS client to compile the styles. On MacOS you can use Dart SASS. Installing it from Homebrew is a matter of one command line:
If you’re not using any NPM dependencies, i.e. don’t have a package.json file, you may go to your project’s root dir and create it with:
Then, add the following scripts to the package.json — notice that if you already have a package.json in your project, the script names below (watch and build) may already exists. In that case, add some suffix to avoid conflicts. watch-styles and build-styles, for instance.
In these scripts, the respective paths to the main SASS file and target CSS files are src/styles/app.scss and dist/styles/app.css. You may have to tweak those paths to match your current project structure.