chore: use the flat config (#72)

Author: ktmouk

.eslintignore

@@ -11,7 +11,7 @@ const removeIgnoredFiles = async (files) => {
   return filteredFiles.join(" ");
 };
 
-export default {
+const config = {
   "**/*.{ts,tsx,js,mjs,jsx}": [
     async (files) => {
       const filesToLint = await removeIgnoredFiles(files);
@@ -22,3 +22,5 @@ export default {
   "*.{md,html,css,scss,json,yml,yaml,md,mdx}": ["prettier -w -u"],
   "**/*": ["secretlint --maskSecrets"],
 };
+
+export default config;

.eslintrc.json

@@ -0,0 +1,49 @@
+import { FlatCompat } from "@eslint/eslintrc";
+import eslintConfigPrettier from "eslint-config-prettier";
+import tseslint from "typescript-eslint";
+
+const compat = new FlatCompat();
+
+/** @type import("eslint").Linter.Config[] */
+const config = tseslint.config(
+  ...compat.config({
+    extends: ["next/core-web-vitals", "next/typescript"],
+  }),
+  tseslint.configs.strictTypeChecked,
+  tseslint.configs.stylisticTypeChecked,
+  {
+    languageOptions: {
+      parserOptions: {
+        projectService: true,
+        tsconfigRootDir: import.meta.dirname,
+      },
+    },
+  },
+  {
+    rules: {
+      "@typescript-eslint/consistent-type-imports": "error",
+      "@typescript-eslint/strict-boolean-expressions": "error",
+      "@typescript-eslint/consistent-type-definitions": ["error", "type"],
+      "import/order": [
+        "error",
+        {
+          "newlines-between": "never",
+          alphabetize: {
+            order: "asc",
+            caseInsensitive: true,
+          },
+        },
+      ],
+    },
+  },
+  {
+    files: ["**/*.mjs"],
+    extends: [tseslint.configs.disableTypeChecked],
+  },
+  {
+    ignores: ["**/out", "**/.next"],
+  },
+  eslintConfigPrettier,
+);
+
+export default config;

.lintstagedrc.mjs

@@ -18,14 +18,18 @@
   "dependencies": {
     "@headlessui/react": "^2.1.1",
     "@radix-ui/react-tooltip": "^1.1.2",
+    "@shikijs/transformers": "^1.10.1",
+    "@typescript-eslint/eslint-plugin": "^8.18.0",
+    "@typescript-eslint/parser": "^8.18.0",
+    "eslint-config-next": "^15.1.0",
+    "eslint-config-prettier": "^9.1.0",
     "next": "^14.2.4",
     "nextra": "^3.0.0",
     "nextra-theme-docs": "^3.0.0",
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
     "react-icons": "^5.2.1",
-    "shiki": "^1.10.1",
-    "@shikijs/transformers": "^1.10.1"
+    "shiki": "^1.10.1"
   },
   "devDependencies": {
     "@secretlint/secretlint-rule-preset-recommend": "^9.0.0",
@@ -34,22 +38,17 @@
     "@types/react": "^19.0.0",
     "@types/react-dom": "^19.0.0",
     "@types/react-syntax-highlighter": "^15.5.13",
-    "@typescript-eslint/eslint-plugin": "^8.0.0",
-    "@typescript-eslint/parser": "^8.0.0",
     "autoprefixer": "^10.4.19",
-    "eslint": "8.57.1",
-    "eslint-config-next": "15.1.0",
-    "eslint-config-prettier": "^9.0.0",
-    "eslint-import-resolver-typescript": "^3.6.1",
-    "eslint-plugin-import": "^2.29.0",
+    "eslint": "9.17.0",
     "husky": "^9.0.11",
     "lint-staged": "^15.0.0",
     "postcss": "^8.4.39",
     "prettier": "^3.2.5",
     "secretlint": "^9.0.0",
     "serve": "^14.2.3",
     "tailwindcss": "^3.4.4",
-    "typescript": "^5.5.3"
+    "typescript": "^5.5.3",
+    "typescript-eslint": "^8.18.0"
   },
   "engines": {
     "node": ">=18",