Improve monorepo eslint config

1. Fix the copyright header lint rule. Extra blank comment lines are now
   avoided. All pragmas are preserved.
2. Get eslint to process `*.mjs` files.
3. Update the React and Flow versions specified in the config.
4. Lint the example directories.

Author: necolas

.eslintrc.js

@@ -7,12 +7,14 @@
  *
  */
 
+const path = require('path');
+
 module.exports = {
   settings: {
     react: {
       pragma: 'React',
-      version: '17.0',
-      flowVersion: '0.214.0', // Flow version
+      version: '18.0',
+      flowVersion: '0.261.2', // Flow version
     },
     'ft-flow': {
       onlyFilesWithFlowAnnotation: true,
@@ -21,7 +23,7 @@ module.exports = {
   // babel parser to support ES6/7 features
   parser: 'hermes-eslint',
   extends: ['plugin:ft-flow/recommended', 'prettier'],
-  plugins: ['ft-flow', 'react', 'header'],
+  plugins: ['ft-flow', 'react', 'headers'],
   env: {
     browser: true,
     es6: true,
@@ -32,7 +34,7 @@ module.exports = {
     'build',
     'coverage',
     'dist',
-    'examples',
+    'flow-typed',
     'lib',
     'node_modules',
     'next-env.d.ts',
@@ -61,19 +63,12 @@ module.exports = {
     Partial: 'readonly',
   },
   rules: {
-    'header/header': [
-      2,
-      'block',
-      [
-        '*',
-        ' * Copyright (c) Meta Platforms, Inc. and affiliates.',
-        ' *',
-        ' * This source code is licensed under the MIT license found in the',
-        ' * LICENSE file in the root directory of this source tree.',
-        ' *',
-        { pattern: '(.*)?', template: ' *' },
-        ' ',
-      ],
+    'headers/header-format': [
+      'error',
+      {
+        source: 'file',
+        path: path.join(__dirname, './tools/eslint/copyright-header.txt'),
+      },
     ],
     camelcase: 0,
     'constructor-super': 2,

examples/example-cli/source/app/Counter.tsx

@@ -3,8 +3,6 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- *
  */
 
 'use client';

examples/example-esbuild/scripts/build.mjs

@@ -3,8 +3,6 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- *
  */
 
 import path from 'path';

examples/example-rollup/rollup.config.mjs

@@ -3,8 +3,6 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- *
  */
 
 import stylexPlugin from '@stylexjs/rollup-plugin';

package-lock.json

@@ -11,7 +11,7 @@
     "prettier": "prettier --write \"**/*.js\" \"**/*.ts\"",
     "prettier:report": "prettier --check \"**/*.js\"",
     "lint": "npm run lint:report -- --fix",
-    "lint:report": "eslint packages tools",
+    "lint:report": "eslint . --ext .js,.jsx,.mjs",
     "release": "tools/npm/release.js",
     "test:packages": "npm run test --workspaces --if-present",
     "test": "npm run build && npm run flow && npm run test:packages && npm run prettier:report && npm run lint:report"
@@ -30,6 +30,7 @@
     "eslint": "8.57.1",
     "eslint-config-prettier": "^9.1.0",
     "eslint-plugin-ft-flow": "^3.0.11",
+    "eslint-plugin-headers": "~1.2.1",
     "eslint-plugin-react": "^7.37.1",
     "flow-bin": "^0.261.2",
     "hermes-eslint": "^0.26.0",

package.json

@@ -3,8 +3,6 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- *
  */
 
 'use strict';

packages/babel-plugin/__tests__/evaluation/stylex-evaluation-test.js

@@ -3,8 +3,6 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- *
  */
 
 'use strict';

packages/babel-plugin/__tests__/evaluation/stylex-fn-obj-evaluation-test.js

@@ -3,8 +3,6 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- *
  */
 
 'use strict';

packages/babel-plugin/__tests__/evaluation/stylex-import-evaluation-test.js

@@ -3,8 +3,6 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- *
  */
 
 'use strict';