fixes eslint config

hosts/dnsc-work/default.nix

@@ -11,6 +11,7 @@
     outputs.nixosModules.macos
     outputs.nixosModules.homebrew
     outputs.nixosModules.aerospace
+    outputs.nixosModules.direnv
   ];
 
   # Device & user-specific settings

modules/nixvim/lsp.nix

@@ -36,6 +36,84 @@
         enable = true;
         package = pkgs.vscode-langservers-extracted;
         packageFallback = true;
+        config = {
+          root_markers = [
+            ".eslintrc"
+            ".eslintrc.js"
+            ".eslintrc.cjs"
+            ".eslintrc.yaml"
+            ".eslintrc.yml"
+            ".eslintrc.json"
+            "eslint.config.js"
+            "eslint.config.mjs"
+            "eslint.config.cjs"
+            "eslint.config.ts"
+            "eslint.config.mts"
+            "eslint.config.cts"
+          ];
+          before_init = /* lua */ ''
+            function(_, config)
+              local eslint_config_files = {
+                ".eslintrc",
+                ".eslintrc.js",
+                ".eslintrc.cjs",
+                ".eslintrc.yaml",
+                ".eslintrc.yml",
+                ".eslintrc.json",
+                "eslint.config.js",
+                "eslint.config.mjs",
+                "eslint.config.cjs",
+                "eslint.config.ts",
+                "eslint.config.mts",
+                "eslint.config.cts",
+              }
+              -- The "workspaceFolder" is a VSCode concept. It limits how far the
+              -- server will traverse the file system when locating the ESLint config
+              -- file (e.g., .eslintrc).
+              local root_dir = config.root_dir
+
+              if root_dir then
+                config.settings = config.settings or {}
+                config.settings.workspaceFolder = {
+                  uri = root_dir,
+                  name = vim.fn.fnamemodify(root_dir, ":t"),
+                }
+
+                -- Support flat config files
+                -- They contain 'config' in the file name
+                local flat_config_files = vim.tbl_filter(function(file)
+                  return file:match("config")
+                end, eslint_config_files)
+
+                for _, file in ipairs(flat_config_files) do
+                  local found_files = vim.fn.globpath(root_dir, file, true, true)
+
+                  -- Filter out files inside node_modules
+                  local filtered_files = {}
+                  for _, found_file in ipairs(found_files) do
+                    if string.find(found_file, "[/\\]node_modules[/\\]") == nil then
+                      table.insert(filtered_files, found_file)
+                    end
+                  end
+
+                  if #filtered_files > 0 then
+                    config.settings.experimental = config.settings.experimental or {}
+                    config.settings.experimental.useFlatConfig = true
+                    break
+                  end
+                end
+
+                -- Support Yarn2 (PnP) projects
+                local pnp_cjs = root_dir .. "/.pnp.cjs"
+                local pnp_js = root_dir .. "/.pnp.js"
+                if vim.uv.fs_stat(pnp_cjs) or vim.uv.fs_stat(pnp_js) then
+                  local cmd = config.cmd
+                  config.cmd = vim.list_extend({ "yarn", "exec" }, cmd)
+                end
+              end
+            end
+          '';
+        };
       };
       biome = {
         enable = true;