v12.1.1 has been released and contains a fix for the issue. Feel free to reopen the issue or to submit a new one if you meet any problems.

Hi there,

I was wondering what was the state if this issue. Recent releases only declares the type as commonjs and with only a main in cjs, esm build isn't exported at all.

In the meantime, I've successfully moved several of my libs with both ESM & CJS support, with auto-fallbacks, so maybe I could give a hand.

On one hand, jest does not support ESM very well: it works, but it needs some time to search, so I'm afraid offering this ability would cause more issues related to ESM specificities with jest, than offering a real improvement. I don't know for jasmine though. Moreover, since this lib is not intended to be built in the application, tree shaking compliance of ESM is not really necessary.
On the other hand, this would be future-proof, possibly helping with future perf improvements and stability of static imports, and eventually support Deno if Angular comes to a point where this is possible.