restore backup and add opencode support

shell.nix

@@ -1,9 +1,9 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import (fetchTarball "https://github.com/NixOS/nixpkgs/archive/refs/tags/20.09.tar.gz") {} }:
 
 let
   lib = import <nixpkgs/lib>;
-  buildNodeJs = pkgs.callPackage "${<nixpkgs>}/pkgs/development/web/nodejs/nodejs.nix" {
-    python = pkgs.python3;
+  buildNodeJs = pkgs.callPackage "${pkgs.path}/pkgs/development/web/nodejs/nodejs.nix" {
+    python = pkgs.python27Full;
   };
 
   nodejsVersion = lib.fileContents ./.nvmrc;
@@ -14,12 +14,18 @@ let
     sha256 = "032801kg24j04xmf09m0vxzlcz86sv21s24lv9l4cfv08k1c4byp";
   };
 
-  # Overlay to use custom nodejs for nodePackages
-  customPkgs = pkgs // { inherit nodejs; };
+  NPM_CONFIG_PREFIX = toString ./npm_config_prefix;
 
-in customPkgs.mkShell {
-  buildInputs = with customPkgs; [
+in pkgs.mkShell {
+  packages = with pkgs; [
     nodejs
     nodePackages."@angular/cli"
   ];
+
+  inherit NPM_CONFIG_PREFIX;
+
+  shellHook = ''
+    export PATH="${NPM_CONFIG_PREFIX}/bin:$PATH"
+    echo "Node version: $(node --version)"
+  '';
 }