Run following commands:

npm i && npm run build

Generated web component file is available in ./elements/my-element.js or http://localhost:4200/assets/my-element.js.

It can be used in LuigiContainer like:

<LuigiContainer viewURL="http://localhost:4200/assets/my-element.js" webComponent='{"selfRegistered":"true"}'/>

or in Luigi core:

{
    pathSegment: 'reactwc',
    label: 'reactwc',
    viewUrl: 'http://localhost:4200/assets/my-element.js',
    webcomponent: {
        selfRegistered: true,
    }
}