node8-env.nix

{ pkgs ? import <nixos> {}
, fetchurl ? pkgs.fetchurl
, buildFHS ? pkgs.buildFHSUserEnv
, mkDerivation ? pkgs.stdenv.mkDerivation
}:
let
    pkgUrl = "https://nodejs.org/dist/v8.4.0/node-v8.4.0-linux-x64.tar.xz";
    pkgSha = "7fd86abad06f96cb2f889c2a0e25686a3de3e9a078ad946ded91ee4f28d8218a";
in rec {
    node-env = mkDerivation {
        name = "node-env";

        src = fetchurl {
            url = pkgUrl;
            sha256 = pkgSha;
        };  

        phases = [ "unpackPhase" "installPhase" ];

        installPhase = ''
            mkdir -p $out
            cp -r * $out
        ''; 
    };  

    node = buildFHS {
        name = "node";
        targetPkgs = pkgs: [ node-env
                             pkgs.git
                           ];  
        runScript = "node";
    };  

    npm = buildFHS {
        name = "npm";
        targetPkgs = pkgs: [ node-env
                             pkgs.git
                           ];  
        runScript = "npm";
    };  
}

shell.nix

let
    pkgs = import <nixpkgs> {}; 
    stdenv = pkgs.stdenv;
    node = import ~/.nixpkgs/node6-env.nix { pkgs = pkgs; };

in stdenv.mkDerivation rec {
    name = "node-working-shell";

    buildInputs = [ node.node
                    node.npm
                  ];

    shellHook = ''
        export PS1="[$name] \[$txtgrn\]\u@\h\[$txtwht\]:\[$bldpur\]\w \[$txtcyn\]\$git_branch\[$txtred
\]\$git_dirty \[$bldylw\]\$aws_env\[$txtrst\]\$ "
    ''; 
}