nix flake so sveske and spoody busts

flake.nix

@@ -0,0 +1,46 @@
+{
+  description = "NPM project (dev shell + run, auto-install deps)";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+        node = pkgs.nodejs_22; # or pkgs.nodejs_20
+        start = pkgs.writeShellApplication {
+          name = "start";
+          runtimeInputs = [ node ];
+          text = ''
+            set -euo pipefail
+            export npm_config_cache="$PWD/.npm-cache"
+            if [ -f package-lock.json ]; then cmd=ci; else cmd=install; fi
+            echo "→ npm $cmd (nix run)"
+            ${node}/bin/npm "$cmd"
+            exec ${node}/bin/npm run dev -- "$@"
+
+          '';
+        };
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          buildInputs = [ node ];
+          shellHook = ''
+            set -euo pipefail
+            export npm_config_cache="$PWD/.npm-cache"
+            if [ -f package-lock.json ]; then cmd=ci; else cmd=install; fi
+            echo "→ npm $cmd (dev shell)"
+            ${node}/bin/npm "$cmd"
+          '';
+        };
+
+        apps.default = {
+          type = "app";
+          program = "${start}/bin/start";
+        };
+      });
+}
+