Quick notes on what worked to package a frontend yarn JS project and how to update gems in an existing Ruby project using bundix for Nix based configuration.

nix-yarn2nix-bundix-packaging.org

Random Nix Project Packaging (yarn2nix, bundix -l)

Setting up a nodejs project via yarn2nix in Nix for existing project

• nix-shell -p yarn yarn2nix nodejs
• copied the Nix skeleton files in place (./z/etc/lib/{version,nixpkgs}.nix ./z/etc/overlays/default.nix)
• generated package.nix using yarn2nix
• add these Nix expressions in the root

# shell.nix
{ pkgs ? import ./z/etc/lib/nixpkgs.nix }:
let
  pkg = import ./. {
    inherit (pkgs) mkYarnPackage;
  };
in pkgs.mkShell {
  buildInputs = with pkgs; [
    nodejs
    yarn
    yarn2nix
    python
    pkg
  ];
}

# default.nix
{ mkYarnPackage }:
mkYarnPackage {
  name = "dailykos-frontend";
  src = ./.;
  packageJson = ./package.json;
  yarnLock = ./yarn.lock;
  yarnNix = ./package.nix;
}

Adding gems to an existing Ruby project for Nix environment

• Edited Gemfile to add gem to appropriate group
• bundix -l
• You might need to add the group to the groups attribute of the bundlerEnv
• Profit!