Add formatter

flake.lock

@@ -35,7 +35,28 @@
     "root": {
       "inputs": {
         "linkita": "linkita",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "treefmt": "treefmt"
+      }
+    },
+    "treefmt": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1760889407,
+        "narHash": "sha256-ppIp04fmz+BaTpJs1nIOmPADg02asfQFrFbhb3SmxsE=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "3f258dead9fed51f53862366d3a6bc1b622ee7cb",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
       }
     }
   },

flake.nix

@@ -2,6 +2,11 @@
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
 
+    treefmt = {
+      url = "github:numtide/treefmt-nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
     linkita = {
       url = "git+https://codeberg.org/salif/linkita.git";
       flake = false;
@@ -11,6 +16,7 @@
   outputs =
     {
       nixpkgs,
+      treefmt,
       linkita,
       ...
     }:
@@ -28,6 +34,14 @@
         '';
       };
 
-      formatter.${system} = pkgs.nixfmt-tree;
+      formatter.${system} =
+        (treefmt.lib.evalModule pkgs {
+          projectRootFile = "flake.nix";
+          programs = {
+            nixfmt.enable = true;
+            prettier.enable = true;
+            just.enable = true;
+          };
+        }).config.build.wrapper;
     };
 }