Hi @TLATER thanks for the reply!
Unfortunately, I don’t think we have a package for modern Yarn (aka Yarn berry, Yarn 2+) from nixpkgs.
The yarn package from nixpkgs is actually Yarn 1 (Classic). You can see the version number at here on the github repo.
It doesn’t throw any error after I run nix-shell with my default.nix. Is it possible to get the logs for the nix-shell command?