Support flat config

e2e-test/flat-config/__snapshots__/index.test.ts.snap

@@ -0,0 +1,3 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`fix problems with flat config 1`] = `"const a = 1;"`;

e2e-test/flat-config/index.test.ts

@@ -0,0 +1,60 @@
+import { afterEach, test, expect } from 'vitest';
+import { createIFF } from '../../src/test-util/fixtures.js';
+import dedent from 'dedent';
+import { ChildProcessWithoutNullStreams, spawn } from 'child_process';
+import { createStreamWatcher } from '../../src/test-util/stream-watcher.js';
+import { readFile } from 'node:fs/promises';
+import { dirname, join } from 'path';
+import { fileURLToPath } from 'url';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+
+const ETX = String.fromCharCode(0x03); // ^C
+const LF = String.fromCharCode(0x0a); // \n
+
+const iff = await createIFF({
+  'src/index.js': 'let a = 1;',
+  'eslint.config.js': dedent`
+    export default [
+      { rules: { 'prefer-const': 'error' } },
+    ];
+  `,
+  'package.json': '{ "type": "module" }',
+});
+
+function waitForClose(child: ChildProcessWithoutNullStreams) {
+  return new Promise<void>((resolve) => {
+    child.on('close', resolve);
+  });
+}
+
+let child: ChildProcessWithoutNullStreams;
+afterEach(async () => {
+  child.kill();
+  await waitForClose(child);
+  await iff.reset();
+});
+
+test('fix problems with flat config', async () => {
+  child = spawn(
+    'node',
+    [
+      join(__dirname, '../../bin/eslint-interactive.js'),
+      'src',
+      // merge stderr to stdout
+      '2>&1',
+    ],
+    { shell: true, stdio: 'pipe', cwd: iff.rootDir, env: { ...process.env, ESLINT_USE_FLAT_CONFIG: 'true' } },
+  );
+  const streamWatcher = createStreamWatcher(child.stdout, { debug: false });
+
+  await streamWatcher.match(/Which rules would you like to apply action\?/);
+  child.stdin.write(' '); // Select `prefer-const` rule
+  child.stdin.write(LF); // Confirm the choice
+  await streamWatcher.match(/Which action do you want to do\?/);
+  child.stdin.write('1'); // Focus on `Run `eslint --fix``
+  child.stdin.write(LF); // Confirm the choice
+  await streamWatcher.match(/Fixing done\./);
+  expect(await readFile(iff.paths['src/index.js'], 'utf-8')).toMatchSnapshot();
+  child.stdin.write(ETX); // Exit
+});

e2e-test/flat-config/package.json

@@ -0,0 +1,6 @@
+{
+  "type": "module",
+  "dependencies": {
+    "eslint-interactive": "../../"
+  }
+}

e2e-test/global-installation/index.test.ts

@@ -36,7 +36,7 @@ test('can print error with eslint-formatter-codeframe', async () => {
     ],
     { shell: true, stdio: 'pipe', cwd: __dirname, env: { ...process.env, ESLINT_USE_FLAT_CONFIG: 'false' } },
   );
-  const streamWatcher = createStreamWatcher(child.stdout, { debug: true });
+  const streamWatcher = createStreamWatcher(child.stdout, { debug: false });
 
   await streamWatcher.match(/Which rules would you like to apply action\?/);
   child.stdin.write(' '); // Select `semi` rule

fixtures/eslint.config.mjs

@@ -0,0 +1,40 @@
+// @ts-check
+
+import { FlatCompat } from '@eslint/eslintrc';
+
+const compat = new FlatCompat();
+
+export default [
+  ...compat.plugins('import'),
+  ...compat.env({ node: true, es2020: true }),
+  {
+    files: ['**/*.js', '**/*.mjs', '**/*.jsx'],
+    languageOptions: {
+      sourceType: 'module',
+      ecmaVersion: 2020,
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+    },
+    rules: {
+      'semi': 2,
+      'import/order': [2, { alphabetize: { order: 'asc' } }],
+      'prefer-const': 2,
+      'no-unused-vars': [
+        2,
+        {
+          ignoreRestSiblings: true,
+          argsIgnorePattern: '^_',
+          caughtErrors: 'all',
+        },
+      ],
+      'ban-exponentiation-operator': 'off', // Disable in flat config
+      'no-useless-escape': 2,
+      'no-unsafe-negation': 2,
+      'arrow-body-style': [2, 'always'],
+
+    },
+  },
+]

package.json

@@ -44,7 +44,7 @@
     "@types/node": "^20.8.10",
     "@types/yargs": "^17.0.29",
     "dedent": "^1.5.1",
-    "eslint": "^8.53.0",
+    "eslint": "^8.57.0",
     "fs-extra": "^11.1.1",
     "import-meta-resolve": "^4.0.0",
     "npm-run-all": "^4.1.5",