Error when trying to generate new lib using `nx` command

Current Behavior

Hi folks, ✋

I’m facing a cryptic error when trying to generate new lib in a Nx repository. I’m running the command yarn nx generate lib my-lib which unexpectedly fails and gives the following output:

>  NX   NOTE  Nx didn't recognize the command, forwarding on to the Angular CLI.
You provided an invalid object where a stream was expected. You can provide an Observable, Promise, Array, or Iterable.
error Command failed with exit code 1.

I tried to directly use the ng command like yarn ng generate lib my-lib and it works well. That’s why I’m opening the issue here.

Expected Behavior

I would like to generate new library using the nx command.

Steps to Reproduce

Simply run yarn nx generate lib my-lib will throw the error. I tried with a fresh new Nx installation and I ran into the same problem.

If you’re willing I can investigate to fix this error.

[jdpearce]

Hi @Edouardbozon - this is down to an incompatibility between your local version of RxJS and the Angular CLI version of RxJS.

Your package.json has ~6.5.0 whereas the Angular CLI version you have installed requires 6.4.0. This bug only manifests when running nx because then it will use the version of RxJS in your package.json not the internal version that Angular CLI installs.

If you downgrade your version of RxJS it will work correctly.

[FrozenPandaz]

This is fixed with https://github.com/nrwl/nx/pull/2046