add nix flake

.envrc

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

.gitignore

@@ -9,3 +9,4 @@
 node_modules
 dist
 test
+.direnv

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1673525234,
+        "narHash": "sha256-fMP37VTeqSzC8JYoQJinLOnHfjriE5uKInLWJRz5K3E=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "92f9580a4c369b4b51a7b6a5e77da43720134c9f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,21 @@
+{
+  description = "Linux Package Manager";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    ...
+  }: let
+    pkgs = nixpkgs.legacyPackages.x86_64-linux;
+  in {
+    devShell.x86_64-linux = pkgs.mkShell {
+      packages = [pkgs.nodePackages.pnpm pkgs.nodejs-18_x];
+    };
+
+    formatter.x86_64-linux = pkgs.alejandra;
+  };
+}