Add and use alejandra to format Nix files

flake.nix

@@ -1,23 +1,34 @@
 {
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
 
-  outputs = inputs@{ self, flake-parts, ... }:
-    flake-parts.lib.mkFlake { inherit inputs; } {
+  outputs = inputs @ {
+    self,
+    flake-parts,
+    ...
+  }:
+    flake-parts.lib.mkFlake {inherit inputs;} {
       flake = {
-        lib = import ./lib { inherit inputs; };
+        lib = import ./lib {inherit inputs;};
       };
 
-      systems = [ "x86_64-linux" ];
+      systems = ["x86_64-linux"];
 
-      perSystem = { pkgs, self', system, ... }:
-        let
-          default = self.lib.mkVimPlugin { inherit system; };
-          neovim = self.lib.mkNeovim { inherit system; };
-        in
-        {
-          packages = { inherit default neovim; };
+      perSystem = {
+        pkgs,
+        self',
+        system,
+        ...
+      }: let
+        default = self.lib.mkVimPlugin {inherit system;};
+        neovim = self.lib.mkNeovim {inherit system;};
+      in {
+        devShells.default = pkgs.mkShell {
+          nativeBuildInputs = [pkgs.just];
+        };
 
-          formatter = pkgs.nixpkgs-fmt;
+        packages = {inherit default neovim;};
+
+        formatter = pkgs.alejandra;
       };
     };
 }

lib/default.nix

@@ -1,11 +1,7 @@
-{ inputs }:
-
-let
+{inputs}: let
   inherit (inputs.nixpkgs) legacyPackages;
-in
-rec {
-  mkVimPlugin = { system }:
-    let
+in rec {
+  mkVimPlugin = {system}: let
     inherit (pkgs) vimUtils;
     inherit (vimUtils) buildVimPlugin;
     pkgs = legacyPackages.${system};
@@ -25,15 +21,14 @@ rec {
       src = ../.;
     };
 
-  mkNeovimPlugins = { system }:
-    let
+  mkNeovimPlugins = {system}: let
     inherit (pkgs) vimPlugins;
 
-      pkgs = (import inputs.nixpkgs {
+    pkgs = import inputs.nixpkgs {
       inherit system;
 
       config.allowUnfree = true;
-      });
+    };
 
     customVim = {
       tabline-vim = pkgs.vimUtils.buildVimPlugin {
@@ -97,9 +92,8 @@ rec {
       };
     };
 
-      opdavies-nvim = mkVimPlugin { inherit system; };
-    in
-    [
+    opdavies-nvim = mkVimPlugin {inherit system;};
+  in [
     customVim.tabline-vim
     customVim.vim-caser
     customVim.vim-heritage
@@ -236,17 +230,15 @@ rec {
     opdavies-nvim
   ];
 
-  mkExtraPackages = { system }:
-    let
+  mkExtraPackages = {system}: let
     inherit (pkgs) nodePackages;
 
-      pkgs = (import inputs.nixpkgs {
+    pkgs = import inputs.nixpkgs {
       inherit system;
 
       config.allowUnfree = true;
-      });
-    in
-    [
+    };
+  in [
     # Languages
     nodePackages.typescript
     pkgs.php81
@@ -272,6 +264,7 @@ rec {
     pkgs.terraform-ls
 
     # Formatters
+    pkgs.alejandra
     pkgs.black
     pkgs.nodePackages.prettier
     pkgs.stylua
@@ -292,29 +285,26 @@ rec {
     EOF
   '';
 
-  mkNeovim = { system }:
-    let
+  mkNeovim = {system}: let
     inherit (pkgs) lib neovim;
-      extraPackages = mkExtraPackages { inherit system; };
+    extraPackages = mkExtraPackages {inherit system;};
     pkgs = legacyPackages.${system};
-      start = mkNeovimPlugins { inherit system; };
+    start = mkNeovimPlugins {inherit system;};
   in
     neovim.override {
       configure = {
         customRC = mkExtraConfig;
-        packages.main = { inherit start; };
+        packages.main = {inherit start;};
       };
 
       extraMakeWrapperArgs = ''--suffix PATH : "${lib.makeBinPath extraPackages}"'';
     };
 
-  mkHomeManager = { system }:
-    let
+  mkHomeManager = {system}: let
     extraConfig = mkExtraConfig;
-      extraPackages = mkExtraPackages { inherit system; };
-      plugins = mkNeovimPlugins { inherit system; };
-    in
-    {
+    extraPackages = mkExtraPackages {inherit system;};
+    plugins = mkNeovimPlugins {inherit system;};
+  in {
     inherit extraConfig extraPackages plugins;
 
     enable = true;

lua/opdavies/lsp/none-ls.lua

@@ -11,6 +11,7 @@ null_ls.setup {
   sources = {
     code_actions.gitsigns,
 
+    formatting.alejandra,
     formatting.black,
     formatting.markdownlint,
     formatting.phpcbf.with {