Angular 9: Value at position X in the NgModule.imports is not a reference

Question

I upgraded an Angular App from v8 to v9. The project imports a custom UI library using Angular 8 and moment.js.

When I build it:

1. It genera

Answer 1

In my case the issue was related to an imported library, that was not Angular v9 compatible (among other things it was not using deep links to Angular Material and moment.js).

I was lucky as the library is an intern one and I could fix these points and republish it. After that it built without any problems or changes in my project.