ember-light-table | Lightweight , contextual component based table for Ember | Addon library

The error kinda hints at this, but it doesn't really make sense unless you're using modern ember -- but you're using 3.4 (thanks for providing that information!!)

The stack in your error is actually very helpful, and here's how you can figure out what the issue is.

I downloaded your reproduction repo (thanks for providing that! reproductions are immensely helpful in debugging!)

I got the same error you did:

The key piece here is the media.js reference. Clicking into that we see:

that the compiled version of the ember-responsive/services/media file is using decorators -- you have some version of ember-responsive in your app which has decorators.

I saw in your package.json that you're specifying on alder version: