Add flake.nix for nodejs

.envrc

@@ -0,0 +1 @@
+use flake .

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1736012469,
+        "narHash": "sha256-/qlNWm/IEVVH7GfgAIyP6EsVZI6zjAx1cV5zNyrs+rI=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "8f3e1f807051e32d8c95cd12b9b421623850a34d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,21 @@
+{
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+
+  outputs =
+    { nixpkgs, ... }:
+    let
+      system = "x86_64-linux";
+      pkgs = nixpkgs.legacyPackages.${system};
+
+      inherit (pkgs) mkShell;
+    in
+    {
+      devShells.${system}.default = mkShell {
+        buildInputs = with pkgs; [
+          nodejs
+        ];
+      };
+
+      formatter.${system} = pkgs.nixfmt-rfc-style;
+    };
+}