Figma Plugin export {}; added during compile causes crash

I have tried to follow this guide:

Now, the code.js file always gets the following added as the last line:
export {};

This then causes the plugin to crash.

I can fix the issue by commenting out or deleting that last line.

The plugin will then run again without issue.

However, the next time I make a change to the code.ts file, the hot reload runs and that line is again added to the bottom of the code.js file, causing the plugin to crash.

What is causing that line to be added?

How to resolve this error please?

Note that:

manifest.json

eslint.config.js

tsconfig.json

package.json