= Nix pinning
:categories: nix

[source,nix]
----
let
  # Pin the nixpkgs version
  stdenv = pkgs.stdenv;
  pkgsOriginal = import <nixpkgs> {};
  pkgsSrc = pkgsOriginal.fetchzip {
    url = "https://github.com/NixOS/nixpkgs/archive/18.03.zip";
    sha256 = "0hk4y2vkgm1qadpsm4b0q1vxq889jhxzjx3ragybrlwwg54mzp4f";
  };

  pkgs = import (pkgsSrc) {};

  buildNodeJS = pkgs.callPackage <nixpkgs/pkgs/development/web/nodejs/nodejs.nix> {};

in rec {
  nodeFromNVMRC = buildNodeJS {
    version = "8.7.0";
    sha256 = "16mml3cwjnq7yf9yd67d2dybav3nvbnk89fkixs1wz7fd26d05ss";
    patches = [];
  };
}
----
