feat(deps): update to eslint 9

eslint/_base.js

@@ -1,49 +1,65 @@
+const { FlatCompat } = require('@eslint/eslintrc');
+const jseslint = require('@eslint/js');
+const eslintImport = require('eslint-plugin-import');
+const eslintComments = require('eslint-plugin-eslint-comments');
+const babelParser = require('@babel/eslint-parser');
+
 const { ECMA_VERSION, JAVASCRIPT_FILES } = require('./constants');
 
 // See: https://github.com/eslint/eslint/issues/3458
-require('@rushstack/eslint-patch/modern-module-resolution');
+// require('@rushstack/eslint-patch/modern-module-resolution');
+
+const { rules: bestPracticeRules } = require('./rules/best-practice');
+const { rules: commentsRules } = require('./rules/comments');
+const { rules: es6Rules } = require('./rules/es6');
+const { rules: importRules } = require('./rules/import');
+const { rules: possibleErrorsRules } = require('./rules/possible-errors');
+const { rules: stylisticRules } = require('./rules/stylistic');
+const { rules: unicornRules } = require('./rules/unicorn');
+const { rules: variablesRules } = require('./rules/variables');
+
+const flatCompat = new FlatCompat({
+  baseDirectory: __dirname,
+});
 
 /**
  * This is the base for both our browser and Node ESLint config files.
  */
-module.exports = {
-  extends: [
-    'eslint:recommended',
-    'plugin:import/recommended',
-    'prettier',
-    require.resolve('./rules/best-practice'),
-    require.resolve('./rules/comments'),
-    require.resolve('./rules/es6'),
-    require.resolve('./rules/import'),
-    require.resolve('./rules/possible-errors'),
-    require.resolve('./rules/stylistic'),
-    require.resolve('./rules/unicorn'),
-    require.resolve('./rules/variables'),
-  ],
-  env: {
+module.exports = [
+  jseslint.configs.recommended,
+  ...flatCompat.plugins('prettier', 'unicorn'),
+  ...flatCompat.config(eslintImport.configs.recommended),
+  ...flatCompat.config(eslintComments.configs.recommended),
+  ...flatCompat.env({
     [`es${ECMA_VERSION}`]: true,
-  },
-  // Report unused `eslint-disable` comments.
-  reportUnusedDisableDirectives: true,
-  // Tell ESLint not to ignore dot-files, which are ignored by default.
-  ignorePatterns: ['!.*.js'],
-  // Global settings used by all overrides.
-  settings: {
-    // Use the Node resolver by default.
-    'import/resolver': { node: {} },
-  },
-  // Global parser options.
-  parserOptions: {
-    ecmaVersion: ECMA_VERSION,
-    sourceType: 'module',
-  },
-  overrides: [
-    {
-      files: JAVASCRIPT_FILES,
-      parser: '@babel/eslint-parser',
+  }),
+  {
+    files: JAVASCRIPT_FILES,
+    languageOptions: {
+      ecmaVersion: ECMA_VERSION,
+      sourceType: 'module',
+      parser: babelParser,
       parserOptions: {
+        // Report unused `eslint-disable` comments.
+        reportUnusedDisableDirectives: true,
         requireConfigFile: false,
       },
     },
-  ],
-};
+    // Tell ESLint not to ignore dot-files, which are ignored by default.
+    ignores: ['!.*.js'],
+    settings: {
+      // Use the Node resolver by default.
+      'import/resolver': { node: {} },
+    },
+    rules: {
+      ...bestPracticeRules,
+      ...commentsRules,
+      ...es6Rules,
+      ...importRules,
+      ...possibleErrorsRules,
+      ...stylisticRules,
+      ...unicornRules,
+      ...variablesRules,
+    },
+  },
+];

eslint/browser.js

@@ -1,6 +1,14 @@
-module.exports = {
-  extends: './_base',
-  env: {
+const { FlatCompat } = require('@eslint/eslintrc');
+
+const baseConfig = require('./_base');
+
+const flatCompat = new FlatCompat({
+  baseDirectory: __dirname,
+});
+
+module.exports = [
+  ...baseConfig,
+  ...flatCompat.env({
     browser: true,
-  },
-};
+  }),
+];

eslint/comments.js

@@ -1,6 +1,17 @@
-module.exports = {
-  extends: [
-    'plugin:eslint-comments/recommended',
-    require.resolve('./rules/comments'),
-  ],
-};
+const { FlatCompat } = require('@eslint/eslintrc');
+const comments = require('eslint-plugin-eslint-comments');
+
+const { rules } = require('./rules/comments');
+
+const flatCompat = new FlatCompat({
+  baseDirectory: __dirname,
+});
+
+module.exports = [
+  ...flatCompat.config(comments.configs.recommended),
+  {
+    rules,
+  },
+];
+
+// 'plugin:eslint-comments/recommended',

eslint/jest-react.js

@@ -1,9 +1,28 @@
-module.exports = {
-  plugins: ['testing-library'],
-  extends: [
-    require.resolve('./jest'),
+const { FlatCompat } = require('@eslint/eslintrc');
+
+const { TYPESCRIPT_FILES } = require('./constants');
+const { rules } = require('./rules/jest');
+
+const flatCompat = new FlatCompat({
+  baseDirectory: __dirname,
+});
+
+module.exports = [
+  ...flatCompat.plugins('testing-library'),
+  ...flatCompat.extends(
     // We may want to separate this out in future, as it's only needed when
     // using React with Testing Library.
     'plugin:testing-library/react',
-  ],
-};
+  ),
+  ...flatCompat.plugins('jest'),
+  {
+    files: TYPESCRIPT_FILES,
+    rules: {
+      ...rules,
+      // Prefer the Jest version of this rule. This silently fails when type
+      // information is not available.
+      '@typescript-eslint/unbound-method': 'off',
+      'jest/unbound-method': 'error',
+    },
+  },
+];

eslint/jest.js

@@ -1,16 +1,22 @@
+const { FlatCompat } = require('@eslint/eslintrc');
+
 const { TYPESCRIPT_FILES } = require('./constants');
+const { rules } = require('./rules/jest');
+
+const flatCompat = new FlatCompat({
+  baseDirectory: __dirname,
+});
 
-module.exports = {
-  extends: ['plugin:jest/recommended', require.resolve('./rules/jest')],
-  overrides: [
-    // Prefer the Jest version of this rule. This silently fails when type
-    // information is not available.
-    {
-      files: TYPESCRIPT_FILES,
-      rules: {
-        '@typescript-eslint/unbound-method': 'off',
-        'jest/unbound-method': 'error',
-      },
+module.exports = [
+  ...flatCompat.plugins('jest'),
+  {
+    files: TYPESCRIPT_FILES,
+    rules: {
+      ...rules,
+      // Prefer the Jest version of this rule. This silently fails when type
+      // information is not available.
+      '@typescript-eslint/unbound-method': 'off',
+      'jest/unbound-method': 'error',
     },
-  ],
-};
+  },
+];

eslint/next.js

@@ -1,25 +1,10 @@
-const { JAVASCRIPT_FILES } = require('./constants');
 const requirePackage = require('./utils/require-package');
 
 requirePackage('next', '@next/eslint-plugin-next');
 
-const babelOptions = {
-  presets: (() => {
-    try {
-      require.resolve('next/babel');
-      return ['next/babel'];
-    } catch (e) {
-      return [];
-    }
-  })(),
-};
+const { FlatCompat } = require('@eslint/eslintrc');
+const next = require('@next/eslint-plugin-next');
 
-module.exports = {
-  extends: ['plugin:@next/next/recommended'],
-  overrides: [
-    {
-      files: JAVASCRIPT_FILES,
-      parserOptions: { babelOptions },
-    },
-  ],
-};
+const flatCompat = new FlatCompat({});
+
+module.exports = [...flatCompat.config(next.configs.recommended)];

eslint/node.js

@@ -1,6 +1,14 @@
-module.exports = {
-  extends: require.resolve('./_base'),
-  env: {
+const { FlatCompat } = require('@eslint/eslintrc');
+
+const baseConfig = require('./_base');
+
+const flatCompat = new FlatCompat({
+  baseDirectory: __dirname,
+});
+
+module.exports = [
+  ...baseConfig,
+  ...flatCompat.env({
     node: true,
-  },
-};
+  }),
+];

eslint/playwright-test.js

@@ -1,7 +1,17 @@
-module.exports = {
-  plugins: ['playwright'],
-  extends: [require.resolve('./rules/playwright-test.js')],
-  env: {
+const { FlatCompat } = require('@eslint/eslintrc');
+
+const { rules } = require('./rules/playwright-test');
+
+const flatCompat = new FlatCompat({
+  baseDirectory: __dirname,
+});
+
+module.exports = [
+  ...flatCompat.plugins('playwright'),
+  ...flatCompat.env({
     'shared-node-browser': true,
+  }),
+  {
+    rules,
   },
-};
+];

eslint/react.js

@@ -1,16 +1,32 @@
-module.exports = {
-  extends: [
-    'plugin:react/recommended',
-    'plugin:react-hooks/recommended',
-    'plugin:jsx-a11y/recommended',
-    'plugin:import/react',
-    'prettier',
-    require.resolve('./rules/react'),
-    require.resolve('./rules/jsx-a11y'),
-  ],
-  settings: {
-    react: {
-      version: 'detect',
+const { FlatCompat } = require('@eslint/eslintrc');
+const react = require('eslint-plugin-react');
+const reactHooks = require('eslint-plugin-react-hooks');
+const jsxA11y = require('eslint-plugin-jsx-a11y');
+const eslintImport = require('eslint-plugin-import');
+
+const { rules: reactRules } = require('./rules/react');
+const { rules: jsxA11yRules } = require('./rules/jsx-a11y');
+
+const flatCompat = new FlatCompat({
+  baseDirectory: __dirname,
+});
+
+module.exports = [
+  ...flatCompat.config(react.configs.recommended),
+  ...flatCompat.config(reactHooks.configs.recommended),
+  ...flatCompat.config(jsxA11y.configs.recommended),
+  ...flatCompat.config(eslintImport.configs.recommended),
+  ...flatCompat.config(eslintImport.configs.react),
+  ...flatCompat.plugins('prettier'),
+  {
+    settings: {
+      react: {
+        version: 'detect',
+      },
+    },
+    rules: {
+      ...reactRules,
+      ...jsxA11yRules,
     },
   },
-};
+];

eslint/rules/comments.js

@@ -1,5 +1,4 @@
 module.exports = {
-  plugins: ['eslint-comments'],
   rules: {
     /**
      * Require comments on ESlint disable directives.

eslint/rules/tsdoc.js

@@ -1,5 +1,4 @@
 module.exports = {
-  plugins: ['eslint-plugin-tsdoc'],
   rules: {
     /**
      * Require TSDoc comments conform to the TSDoc specification.

eslint/rules/unicorn.js

@@ -1,6 +1,13 @@
+/**
+ * These are enabled by `unicorn/recommended`.
+ */
+const disabledRules = {
+  'unicorn/prevent-abbreviations': 'off',
+};
+
 module.exports = {
-  plugins: ['unicorn'],
   rules: {
+    ...disabledRules,
     /**
      * Require consistent filename case for all linted files.
      *