ERROR in node_modules/mat-table-exporter/lib/mat-table-exporter.module.d.ts:1:22 - error NG6002: Appears in the NgModule.imports of AppModule, but could not be resolved to an NgModule class. about ng-material-extensions

[HalitTalha]

mat-table-exporter and other ng-material-extension packages are not Ivy compiled however they should be compatible. For the time being you can disable Ivy if it is possible in your case.

[HalitTalha]

Thank you for the feedback 👍 Actually it is nothing to do with the Ivy in our case. If a library is compiled with Ivy, non-ivy applications can not use it. That's why Angular team does recommend library authers to keep going with the old view-engine untill Angular 10. Because a view-engine compiled library can be used by both ivy and view engine compiled applications.
I couldn't have the chance to reproduce your case yet but it seems somehow ng-material-extensions implies an incompatibility with ngcc (Angular compatibility compiler)
I believe I can resolve this this week before our planned patch release.

[itayperry]

Thank you so much for your fast reply! I might need to use Ivy in the near future. Any idea how long it would take for ng-material-extension to be Ivy compiled? If it’s being planned or something.. and thanks again for your answer.

[itayperry]

So maybe I got it all wrong, perhaps it's truly an ngcc compatibility issue. I wasn't aware of Angular's recommendations for the authors and that

"view-engine compiled library can be used by both ivy and view engine compiled applications."

Thank you for explaining all of this :)
Should I reinstall in a week or two and try it out?

[HalitTalha]

I finally got the time to check and validate the packages are ivy compatible. If your issue is still there could you send your package.json?

You can take a look at this example project which is in Angular 9.1.3 version as in your case.
https://github.com/HalitTalha/ivy-testing

[HalitTalha]

Closing due to inactivity.