Ionic 3 Angular Build without Ionic Scripts / CLI

Yes, Ionic 3. It’s a huge project with several apps which cannot simply migrate to Ionic 4 / 5. Not yet. But I’m thinking about multi-app (monorepo) improvements. A step by step process for my repo to update to the latest Ionic version later.

How to build an Ionic 3 project without using the Ionic Scripts? My idea is to build the Angular project by e.g. ng build and later bundle it with cordova commands.
I tried this in Ionic 4 and it works. But in Ionic 3 it seems to be a special Angular version.
I guess I need the angular-cli.json or something like this.

More background: The goal is a monorepo with only one package.json and single dependencies with mulitple apps. In Ionic 4 I created a small script to build the Angular project by ng build and build the apk with cordova build android --release etc. … The first obstacle is the ng build in Ionic 3. Any idea or experience will help me. An update to Ionic 4+ is not possible at this moment. …

Sadly, this is not realllly possible with v3 apps. V3 apps are very tied to app-scripts given how we used the @IonicPage decorator to generate the router information.

I would reallly suggest going the v5 migration route vs trying to force a v3 app to fit. You’ll probably spend less time in the migration than trying to get a v3 app to work with new angular tooling.