Can't resolve all parameters for AppComponent

Problem was solved by adding Inject directive to Service in AppComponent

constructor(@Inject(AppService) service: AppService)

After 1 day on this I realized I had removed some polyfills I didn't think I need. This is what I was missing: import 'core-js/es7/reflect'; see https://github.com/angular/angular/issues/19417#issuecomment-359722822 for more info.

Try to put semicolon after this line in your app.module.shared.ts:

import { AppService } from './app.service' 

we can get this error for various reasons like: Syntax error, duplicate comma, or missing a semicolon