webpackJsonp is not defined

Ionic app seems to have stopped working and I am not able pinpoint the cause. I started again from blank app, but this error persists

Not sure if I am missing setup steps or issue with version mismatch? any pointers would help as I have wasted weeks on this issue

Accepted answers, like - WebpackJsonp missing after Ionic 3 update or Ionic 2: ReferenceError: webpackJsonp is not defined have not worked

index.html has

ionic info -
cli packages: (/usr/local/lib/node_modules)

@ionic/cli-utils : 1.19.2
ionic (Ionic CLI) : 3.20.0
global packages:

cordova (Cordova CLI) : 8.0.0
local packages:

@ionic/app-scripts : 3.1.8
Cordova Platforms : android 6.4.0 ios 4.5.4
Ionic Framework : ionic-angular 3.9.2

Android SDK Tools : 26.1.1
ios-deploy : 1.9.2
Node : v9.5.0
npm : 5.7.1
service.worker.js has-

// pre-cache our key assets

have you solved this issue? been losing time trying to figure out what could be wrong.

Same here. It was used to work, but stoped with the message “webpackJsonp not found”.
I’m trying to find the stable packages versions.
Any help?