Install the dependencies...
cd unsecure_es_checker
npm install
...then start Rollup:
npm run dev
Navigate to localhost:3000. You should see the app running.
If you're using Visual Studio Code we recommend installing the official extension Svelte for VS Code. If you are using other editors you may need to install a plugin in order to get syntax highlighting and intellisense.
To create an optimised version of the app:
npm run build
You can run the newly built app with npm run start
. This uses sirv, which is included in package.json's dependencies