feat: support ESLint v9

eslint.config.mjs

@@ -95,7 +95,8 @@ export default tseslint.config(
  },
  rules: {
  // make sure we're not leveraging any deprecated APIs
- 'deprecation/deprecation': 'error',
+ // TODO: Bring this back in once it supports ESLint 9
+ // 'deprecation/deprecation': 'error',
 
  // TODO(#7130): Investigate changing these in or removing these from presets
  '@typescript-eslint/no-confusing-void-expression': 'off',
@@ -239,11 +240,13 @@ export default tseslint.config(
  // disallow non-import statements appearing before import statements
  'import/first': 'error',
  // Require a newline after the last import/require in a group
- 'import/newline-after-import': 'error',
+ // TODO: Bring this back in once it supports ESLint 9
+ // 'import/newline-after-import': 'error',
  // Forbid import of modules using absolute paths
  'import/no-absolute-path': 'error',
  // disallow AMD require/define
- 'import/no-amd': 'error',
+ // TODO: Bring this back in once it supports ESLint 9
+ // 'import/no-amd': 'error',
  // forbid default exports - we want to standardize on named exports so that imported names are consistent
  'import/no-default-export': 'error',
  // disallow imports from duplicate paths
@@ -258,7 +261,8 @@ export default tseslint.config(
  },
  ],
  // Forbid mutable exports
- 'import/no-mutable-exports': 'error',
+ // TODO: Bring this back in once it supports ESLint 9
+ // 'import/no-mutable-exports': 'error',
  // Prevent importing the default as if it were named
  'import/no-named-default': 'error',
  // Prohibit named exports
@@ -299,7 +303,7 @@ export default tseslint.config(
  extends: [tseslint.configs.disableTypeChecked],
  rules: {
  // turn off other type-aware rules
- 'deprecation/deprecation': 'off',
+ // 'deprecation/deprecation': 'off',
  '@typescript-eslint/internal/no-poorly-typed-ts-props': 'off',
 
  // turn off rules that don't apply to JS code
@@ -498,21 +502,25 @@ export default tseslint.config(
  files: ['packages/website/**/*.{ts,tsx,mts,cts,js,jsx}'],
  extends: [
  ...compat.config(jsxA11yPlugin.configs.recommended),
- ...compat.config(reactPlugin.configs.recommended),
- ...compat.config(reactHooksPlugin.configs.recommended),
+ // TODO: Bring this back in once it supports ESLint 9
+ // https://github.com/jsx-eslint/eslint-plugin-react/issues/3699
+ // ...compat.config(reactPlugin.configs.recommended),
+ // TODO: Bring this back in once it supports ESLint 9
+ // https://github.com/facebook/react/issues/28313
+ // ...compat.config(reactHooksPlugin.configs.recommended),
  ],
  rules: {
  '@typescript-eslint/internal/prefer-ast-types-enum': 'off',
  'import/no-default-export': 'off',
- 'react/jsx-no-target-blank': 'off',
- 'react/no-unescaped-entities': 'off',
- 'react-hooks/exhaustive-deps': 'warn', // TODO: enable it later
- },
- settings: {
- react: {
- version: 'detect',
- },
+ // 'react/jsx-no-target-blank': 'off',
+ // 'react/no-unescaped-entities': 'off',
+ // 'react-hooks/exhaustive-deps': 'warn', // TODO: enable it later
  },
+ // settings: {
+ // react: {
+ // version: 'detect',
+ // },
+ // },
  },
  {
  files: ['packages/website/src/**/*.{ts,tsx,cts,mts}'],

package.json

@@ -62,7 +62,7 @@
  "@babel/eslint-parser": "^7.24.1",
  "@babel/parser": "^7.24.4",
  "@babel/types": "^7.24.0",
- "@eslint/eslintrc": "^2.1.4",
+ "@eslint/eslintrc": "^3.0.2",
  "@eslint/js": "^8.57.0",
  "@nx/eslint": "18.2.3",
  "@nx/jest": "18.2.3",
@@ -87,7 +87,7 @@
  "cross-fetch": "^4.0.0",
  "cspell": "^8.6.1",
  "downlevel-dts": ">=0.11.0",
- "eslint": "8.57.0",
+ "eslint": "9.1.1",
  "eslint-plugin-deprecation": "^2.0.0",
  "eslint-plugin-eslint-comments": "^3.2.0",
  "eslint-plugin-eslint-plugin": "^5.5.0",
@@ -124,6 +124,8 @@
  "yargs": "17.7.2"
  },
  "resolutions": {
+ "@eslint/eslintrc": "^3.0.2",
+ "@eslint/js": "9.1.1",
  "@jest/create-cache-key-function": "^29",
  "@jest/reporters": "^29",
  "@jest/test-result": "^29",
@@ -133,7 +135,7 @@
  "@types/estree": "link:./tools/dummypkg",
  "@types/node": "^20.0.0",
  "@types/react": "^18.2.14",
- "eslint": "8.57.0",
+ "eslint": "9.1.1",
  "eslint-visitor-keys": "^3.4.1",
  "jest-config": "^29",
  "jest-resolve": "^29",

packages/eslint-plugin/package.json

@@ -103,7 +103,7 @@
  },
  "peerDependencies": {
  "@typescript-eslint/parser": "^7.0.0",
- "eslint": "^8.57.0"
+ "eslint": "^8.57.0 || ^9.0.0"
  },
  "peerDependenciesMeta": {
  "typescript": {

packages/eslint-plugin/rules.d.ts

@@ -42,5 +42,6 @@ export type TypeScriptESLintRules = Record<
  RuleModule<string, unknown[]>
 >;
 declare const rules: TypeScriptESLintRules;
-// eslint-disable-next-line import/no-default-export
+// TODO: Bring this back in once it supports ESLint 9
+// (eslint-disable-next-line) import/no-default-export
 export default rules;

packages/eslint-plugin/src/rules/no-unused-vars.ts

@@ -433,6 +433,9 @@ export default createRule<Options, MessageIds>({
  };
 
  context.report({
+ node: writeReferences.length
+ ? writeReferences[writeReferences.length - 1].identifier
+ : unusedVar.identifiers[0],
  loc,
  messageId: 'unusedVar',
  data: unusedVar.references.some(ref => ref.isWrite())

packages/eslint-plugin/tests/docs.test.ts

@@ -100,7 +100,7 @@ function renderLintResults(code: string, errors: Linter.LintMessage[]): string {
  return output.join('\n').trim() + '\n';
 }
 
-const linter = new Linter();
+const linter = new Linter({ configType: 'eslintrc' });
 linter.defineParser('@typescript-eslint/parser', tseslintParser);
 
 const eslintOutputSnapshotFolder = path.resolve(

packages/eslint-plugin/tests/rules/array-type.test.ts

@@ -1924,7 +1924,7 @@ interface FooInterface {
 // -- eslint rule tester is not working with multi-pass
 // https://github.com/eslint/eslint/issues/11187
 describe('array-type (nested)', () => {
- const linter = new TSESLint.Linter();
+ const linter = new TSESLint.Linter({ configType: 'eslintrc' });
  linter.defineRule('array-type', rule);
  linter.defineParser('@typescript-eslint/parser', parser);
 

packages/eslint-plugin/tests/rules/consistent-type-assertions.test.ts

@@ -1,4 +1,5 @@
-/* eslint-disable deprecation/deprecation -- TODO - migrate this test away from `batchedSingleLineTests` */
+// TODO: Bring this back in once it supports ESLint 9
+/* (eslint-disable) deprecation/deprecation -- TODO - migrate this test away from `batchedSingleLineTests` */
 
 import { RuleTester } from '@typescript-eslint/rule-tester';
 

packages/eslint-plugin/tests/rules/no-unused-vars/no-unused-vars-eslint.test.ts

@@ -16,17 +16,25 @@ const ruleTester = new RuleTester({
  },
 });
 
-ruleTester.defineRule('use-every-a', context => {
- /**
- * Mark a variable as used
- */
- function useA(node: TSESTree.Node): void {
- context.sourceCode.markVariableAsUsed('a', node);
- }
- return {
- VariableDeclaration: useA,
- ReturnStatement: useA,
- };
+ruleTester.defineRule('use-every-a', {
+ create: context => {
+ /**
+ * Mark a variable as used
+ */
+ function useA(node: TSESTree.Node): void {
+ context.sourceCode.markVariableAsUsed('a', node);
+ }
+ return {
+ VariableDeclaration: useA,
+ ReturnStatement: useA,
+ };
+ },
+ defaultOptions: [],
+ meta: {
+ messages: {},
+ type: 'problem',
+ schema: [],
+ },
 });
 
 /**

packages/eslint-plugin/tests/rules/no-unused-vars/no-unused-vars.test.ts

@@ -20,9 +20,17 @@ const withMetaParserOptions = {
 };
 
 // this is used to ensure that the caching the utility does does not impact the results done by no-unused-vars
-ruleTester.defineRule('collect-unused-vars', context => {
- collectUnusedVariables(context);
- return {};
+ruleTester.defineRule('collect-unused-vars', {
+ create(context) {
+ collectUnusedVariables(context);
+ return {};
+ },
+ defaultOptions: [],
+ meta: {
+ messages: {},
+ type: 'problem',
+ schema: [],
+ },
 });
 
 ruleTester.run('no-unused-vars', rule, {

packages/eslint-plugin/tests/rules/strict-boolean-expressions.test.ts

@@ -1,4 +1,5 @@
-/* eslint-disable deprecation/deprecation -- TODO - migrate this test away from `batchedSingleLineTests` */
+// TODO: Bring this back in once it supports ESLint 9
+/* (eslint-disable) deprecation/deprecation -- TODO - migrate this test away from `batchedSingleLineTests` */
 
 import { noFormat, RuleTester } from '@typescript-eslint/rule-tester';
 import * as path from 'path';

packages/integration-tests/fixtures/legacy-config/.eslintrc.js

@@ -0,0 +1,23 @@
+const eslint = require('@eslint/js');
+const tseslint = require('typescript-eslint');
+
+module.exports = tseslint.config({
+ extends: [
+ eslint.configs.recommended,
+ ...tseslint.configs.recommendedTypeChecked,
+ ],
+ languageOptions: {
+ parser: tseslint.parser,
+ parserOptions: {
+ project: true,
+ tsconfigRootDir: __dirname,
+ },
+ },
+ plugins: {
+ '@typescript-eslint': tseslint.plugin,
+ },
+ rules: {
+ '@typescript-eslint/no-unsafe-argument': 'warn',
+ '@typescript-eslint/no-unsafe-return': 'warn',
+ },
+});

packages/integration-tests/fixtures/legacy-config/file.ts

@@ -0,0 +1,8 @@
+async function unsafeLog(...values: any[]) {
+ for (const value of values) {
+ console.log(value.toUpperCase());
+ }
+ return values;
+}
+
+unsafeLog();

packages/integration-tests/fixtures/legacy-config/package.json

@@ -0,0 +1 @@
+{}

packages/integration-tests/fixtures/legacy-config/tsconfig.json

@@ -0,0 +1,7 @@
+{
+ "compilerOptions": {
+ "noEmit": true,
+ "strict": true
+ },
+ "include": ["file.ts"]
+}