add nix dev shell

.envrc

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

.gitignore

@@ -1,2 +1,3 @@
 npm/
-.cov/
+.cov/
+.direnv/

flake.lock

@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": "nixpkgs-lib"
+      },
+      "locked": {
+        "lastModified": 1777988971,
+        "narHash": "sha256-qIoWPDs+0/8JecyYgE3gpKQxW/4bLW/gp45vow9ioCQ=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "0678d8986be1661af6bb555f3489f2fdfc31f6ff",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1777954456,
+        "narHash": "sha256-hGdgeU2Nk87RAuZyYjyDjFL6LK7dAZN5RE9+hrDTkDU=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "549bd84d6279f9852cae6225e372cc67fb91a4c1",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-lib": {
+      "locked": {
+        "lastModified": 1777168982,
+        "narHash": "sha256-GOkGPcboWE9BmGCRMLX3worL4EMnsnG8MyKmXNeYuhQ=",
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "rev": "f5901329dade4a6ea039af1433fb087bd9c1fe14",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-parts": "flake-parts",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,36 @@
+{
+  description = "Description for the project";
+
+  inputs = {
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  };
+
+  outputs = inputs@{ flake-parts, ... }:
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      imports = [
+        # To import an internal flake module: ./other.nix
+        # To import an external flake module:
+        #   1. Add foo to inputs
+        #   2. Add foo as a parameter to the outputs function
+        #   3. Add here: foo.flakeModule
+
+      ];
+      systems = [ "x86_64-linux" "aarch64-linux" "aarch64-darwin" "x86_64-darwin" ];
+      perSystem = { config, self', inputs', pkgs, system, ... }: {
+       devShells.default = pkgs.mkShellNoCC {
+        packages = with pkgs; [
+          biome
+          deno
+          nodejs_24
+        ];
+       };
+      };
+      flake = {
+        # The usual flake attributes can be defined here, including system-
+        # agnostic ones like nixosModule and system-enumerating ones, although
+        # those are more easily expressed in perSystem.
+
+      };
+    };
+}