Site cannot be installed: the page does not work offline

[Lars-jnk]

After downloading (webpack branch), "npm install" and "npm run dev" I can't add the page to homescreen and the pwa doesn't work offline.

"npm run prod" break up after:

Entrypoint undefined = index.html
[0] ./node_modules/html-webpack-plugin/lib/loader.js!./src/index.html 2.84 KiB {0} [built]
[2] (webpack)/buildin/global.js 489 bytes {0} [built]
[3] (webpack)/buildin/module.js 497 bytes {0} [built]
+ 1 hidden module
Child mini-css-extract-plugin node_modules/css-loader/index.js!src/styles.css:
Entrypoint mini-css-extract-plugin = *
[0] ./node_modules/css-loader!./src/styles.css 3.54 KiB {0} [built]
+ 1 hidden module
<<

The tutorial (https://vaadin.com/pwa/build/production-pwa-with-webpack-and-workbox) has some typos...

Sry, I'm new at PWA and JS. So I don't know how to fix this.