build: migrate prettier config to typescript and remove eslint-plugin-prettier

This change moves from using `eslint-prettier-plugin` to using `eslint-config-prettier` and prettier directly for format checking.

A result of us never running prettier on the root files, is that there were some adjustments needed.  I ran prettier on the repo and have added those changes too.

Lastly, I moved the config to `typescript`.

Author: michaelfaith

.github/renovate.json

@@ -1,4 +1,4 @@
 {
-    "$schema": "https://docs.renovatebot.com/renovate-schema.json",
-    "extends": ["github>eslint/eslint//.github/renovate.json5"]
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": ["github>eslint/eslint//.github/renovate.json5"]
 }

.github/workflows/main.yml

@@ -34,6 +34,7 @@ jobs:
           node-version: 'lts/*'
       - run: npm install
       - run: npm run lint
+      - run: npm run format:check
 
   test-remote:
     name: eslint-remote-tester

.markdownlint.json

@@ -1,4 +1,7 @@
 {
   "line-length": false,
-  "no-inline-html": false
+  "no-inline-html": false,
+  "no-duplicate-heading": {
+    "siblings_only": true
+  }
 }

CHANGELOG.md

@@ -1,5 +1,4 @@
-The MIT License (MIT)
-=====================
+# The MIT License (MIT)
 
 Copyright © 2016 Teddy Katz
 

LICENSE.md

@@ -2,9 +2,12 @@ import path from 'node:path';
 import { fileURLToPath } from 'node:url';
 import js from '@eslint/js';
 import { FlatCompat } from '@eslint/eslintrc';
+import prettier from 'eslint-config-prettier/flat';
 import markdown from 'eslint-plugin-markdown';
 import pluginN from 'eslint-plugin-n';
 import tseslint from 'typescript-eslint';
+import unicorn from 'eslint-plugin-unicorn';
+
 import eslintPlugin from './lib/index.js';
 
 const dirname = path.dirname(fileURLToPath(import.meta.url));
@@ -25,9 +28,8 @@ export default tseslint.config([
   ...compat.extends(
     'not-an-aardvark/node',
     'plugin:@eslint-community/eslint-comments/recommended',
-    'plugin:prettier/recommended',
-    'plugin:unicorn/recommended',
   ),
+  unicorn.configs.recommended,
   pluginN.configs['flat/recommended'],
   {
     rules: {
@@ -91,4 +93,5 @@ export default tseslint.config([
       'unicorn/filename-case': 'off',
     },
   },
+  prettier,
 ]);

eslint.config.ts

@@ -12,6 +12,8 @@
   "license": "MIT",
   "scripts": {
     "build": "tsup",
+    "format": "prettier --write .",
+    "format:check": "prettier --check .",
     "lint": "npm-run-all --continue-on-error --aggregate-output --parallel lint:*",
     "lint:docs": "markdownlint \"**/*.md\"",
     "lint:eslint-docs": "npm-run-all -s build \"update:eslint-docs -- --check\"",
@@ -69,8 +71,7 @@
     "eslint-doc-generator": "^2.2.2",
     "eslint-plugin-markdown": "^5.1.0",
     "eslint-plugin-n": "^17.21.0",
-    "eslint-plugin-prettier": "^5.5.3",
-    "eslint-plugin-unicorn": "^56.0.1",
+    "eslint-plugin-unicorn": "^60.0.0",
     "eslint-remote-tester": "^4.0.3",
     "eslint-scope": "^8.0.1",
     "espree": "^10.0.1",
@@ -80,7 +81,7 @@
     "markdownlint-cli": "^0.43.0",
     "npm-package-json-lint": "^8.0.0",
     "npm-run-all2": "^7.0.1",
-    "prettier": "^3.4.1",
+    "prettier": "^3.6.2",
     "release-it": "^17.2.0",
     "tsup": "^8.5.0",
     "typescript": "^5.9.2",

package.json

@@ -1,3 +1,7 @@
-export default {
+import { type Config } from 'prettier';
+
+const config: Config = {
   singleQuote: true,
 };
+
+export default config;