repo: switch to flat config (#15)

We can use flat configs to lint the repo itself.

Author: 43081j

.env.yarn

@@ -1 +0,0 @@
-ESLINT_USE_FLAT_CONFIG=false

.eslintrc.js

@@ -0,0 +1,94 @@
+const eslintjs = require('@eslint/js');
+const { defineConfig } = require('eslint/config');
+const globals = require('globals');
+const eslintPlugin = require('eslint-plugin-eslint-plugin');
+const importPlugin = require('eslint-plugin-import-x');
+const flowPlugin = require('eslint-plugin-ft-flow');
+const { FlatCompat } = require('@eslint/eslintrc');
+const babelParser = require('@babel/eslint-parser');
+const prettierConfig = require('eslint-config-prettier');
+
+const compat = new FlatCompat({
+  baseDirectory: __dirname,
+});
+
+module.exports = defineConfig([
+  {
+    ignores: ['lib', 'reports', 'examples'],
+  },
+  {
+    files: [
+      'src/**/*.js',
+      'scripts/**/*.js',
+      '__tests__/**/*.js',
+      '__mocks__/**/*.js',
+    ],
+    plugins: {
+      eslint: eslintjs,
+      'eslint-plugin': eslintPlugin,
+      'ft-flow': flowPlugin,
+      'import-x': importPlugin.flatConfigs.recommended.plugins['import-x'],
+    },
+    languageOptions: {
+      globals: {
+        ...globals.node,
+      },
+      parser: babelParser,
+    },
+    extends: [
+      eslintjs.configs.recommended,
+      importPlugin.flatConfigs.recommended,
+    ],
+    rules: {
+      ...prettierConfig.rules,
+      'no-template-curly-in-string': 'off',
+      'import-x/no-extraneous-dependencies': 'error',
+    },
+    settings: {
+      'import-x/resolver': 'typescript',
+    },
+  },
+  ...compat.config(flowPlugin.configs.recommended).map(config => ({
+    ...config,
+    files: [
+      'src/**/*.js',
+      'flow/*.js',
+      '__mocks__/**/*.js',
+      '__tests__/**/*.js',
+    ],
+  })),
+  {
+    files: ['src/rules/*'],
+    extends: [eslintPlugin.configs['flat/rules-recommended']],
+    rules: {
+      'eslint-plugin/require-meta-docs-description': [
+        'error',
+        {
+          pattern: '^(Enforce|Require|Disallow)',
+        },
+      ],
+      'eslint-plugin/require-meta-docs-url': [
+        'error',
+        {
+          pattern:
+            'https://github.com/es-tooling/eslint-plugin-jsx-a11y-x/tree/HEAD/docs/rules/{{name}}.md',
+        },
+      ],
+      'eslint-plugin/require-meta-type': 'off',
+      // disable temporarily
+      'eslint-plugin/prefer-message-ids': 'off',
+    },
+  },
+  {
+    files: ['__tests__/src/rules/*.js'],
+    extends: [eslintPlugin.configs['flat/tests-recommended']],
+  },
+  {
+    files: ['__tests__/**/*'],
+    languageOptions: {
+      globals: {
+        jest: true,
+      },
+    },
+  },
+]);

eslint.config.js

@@ -32,7 +32,7 @@
     "generate-list-of-rules": "eslint-doc-generator --rule-doc-title-format prefix-name --rule-doc-section-options false --config-emoji recommended,☑️ --ignore-config flat/recommended --ignore-config flat/strict",
     "lint": "yarn lint:js && yarn lint:docs",
     "lint:docs": "yarn generate-list-of-rules --check",
-    "lint:js": "eslint .",
+    "lint:js": "eslint",
     "lint:js:fix": "yarn lint:js --fix",
     "pregenerate-list-of-rules": "yarn build",
     "prepublishOnly": "yarn lint && yarn flow && yarn tests-only",
@@ -73,6 +73,7 @@
     "@babel/register": "^7.25.9",
     "@changesets/changelog-github": "^0.5.1",
     "@changesets/cli": "^2.29.4",
+    "@eslint/eslintrc": "^3.3.1",
     "@eslint/js": "^9.26.0",
     "auto-changelog": "^2.5.0",
     "babel-plugin-add-module-exports": "^1.0.4",
@@ -87,6 +88,7 @@
     "eslint-plugin-import-x": "^4.11.1",
     "estraverse": "^5.3.0",
     "flow-bin": "^0.147.0",
+    "hermes-eslint": "^0.28.1",
     "in-publish": "^2.0.1",
     "jackspeak": "=2.1.1",
     "jscodeshift": "^17.0.0",

package.json

@@ -3805,6 +3805,7 @@ __metadata:
     "@babel/register": "npm:^7.25.9"
     "@changesets/changelog-github": "npm:^0.5.1"
     "@changesets/cli": "npm:^2.29.4"
+    "@eslint/eslintrc": "npm:^3.3.1"
     "@eslint/js": "npm:^9.26.0"
     aria-query: "npm:^5.3.2"
     array-includes: "npm:^3.1.8"
@@ -3828,6 +3829,7 @@ __metadata:
     estraverse: "npm:^5.3.0"
     flow-bin: "npm:^0.147.0"
     hasown: "npm:^2.0.2"
+    hermes-eslint: "npm:^0.28.1"
     in-publish: "npm:^2.0.1"
     jackspeak: "npm:=2.1.1"
     jscodeshift: "npm:^17.0.0"
@@ -4549,6 +4551,33 @@ __metadata:
   languageName: node
   linkType: hard
 
+"hermes-eslint@npm:^0.28.1":
+  version: 0.28.1
+  resolution: "hermes-eslint@npm:0.28.1"
+  dependencies:
+    esrecurse: "npm:^4.3.0"
+    hermes-estree: "npm:0.28.1"
+    hermes-parser: "npm:0.28.1"
+  checksum: 10c0/1998bb1e957be3f2b5f195e77d25999085cf658509b2c51c191b3cf752a45f4f93561e175a70ccf0c3f590db5d09a827e0e3cfe7b8470f123ee757ffd1f884df
+  languageName: node
+  linkType: hard
+
+"hermes-estree@npm:0.28.1":
+  version: 0.28.1
+  resolution: "hermes-estree@npm:0.28.1"
+  checksum: 10c0/aa00f437c82099b9043e384b529c75de21d0111b792ab7480fe992975b5f9535a8581664789db197824a7825ea66d2fd70eb20cb568c5315804421deaf009500
+  languageName: node
+  linkType: hard
+
+"hermes-parser@npm:0.28.1":
+  version: 0.28.1
+  resolution: "hermes-parser@npm:0.28.1"
+  dependencies:
+    hermes-estree: "npm:0.28.1"
+  checksum: 10c0/c6d3c01fb1ea5232f4587b6b038f5c2c6414932e7c48efbe156ab160e2bcaac818c9eb2f828f30967a24b40f543cad503baed0eedf5a7e877852ed271915981f
+  languageName: node
+  linkType: hard
+
 "http-cache-semantics@npm:^4.1.1":
   version: 4.2.0
   resolution: "http-cache-semantics@npm:4.2.0"