nix expression that provides a way to copy your zsh configuration files

example.nix

{ pkgs ? import <nixpkgs> {}
, zdotdir ? import (builtins.fetchurl {
    url = "https://gist.githubusercontent.com/damianbaar/57aff242d06c75444dbd36bf5400060e/raw/83d074d45c81a18402146cadc595a20b91bb1985/zdotdir.nix";
  }) { inherit pkgs; }
}:
pkgs.stdenv.mkDerivation {
  name = "withZshEnv";
  shellHook= zdotdir {
    zshenv = builtins.path { path = ./zdotdir/zshenv; };
    zshrc = builtins.path { path = ./zdotdir/zshrc; };
    shellHook= ''
      echo "welcome welcome"
    '';
  };
}

zdotdir.nix

{ pkgs ? import <nixpkgs> {}
, lib ? import <nixpkgs/lib>
}:
{ zshenv ? ""
, zshrc  ? "" 
, shellHook ? ""
}:
let
  getContentOfFile = content: 
    if lib.strings.isStorePath content 
      then builtins.readFile content 
      else content;

  mkZshDotFile = fileName: content: builtins.toFile fileName content;

  zshrcContent = getContentOfFile zshrc;
  zshenvContent  = getContentOfFile zshenv;

  zDotDir = pkgs.stdenv.mkDerivation {
    name = "ZDOTDIR";
    phases = ["installPhase"];
    installPhase = ''
      mkdir $out
      cp ${mkZshDotFile "zshenv" zshenvContent} $out/.zshenv
      cp ${mkZshDotFile "zshrc" zshrcContent} $out/.zshrc
    '';
  };
in ''
  export ZDOTDIR=${zDotDir}
  ${shellHook}
''