eslint.config.mjs

// For more info, see https://github.com/storybookjs/eslint-plugin-storybook#configuration-flat-config-format
import storybook from 'eslint-plugin-storybook';
import prettier from 'eslint-plugin-prettier';
import prettierConfig from 'eslint-config-prettier';

import { defineConfig, globalIgnores } from 'eslint/config';
import nextVitals from 'eslint-config-next/core-web-vitals';
import nextTs from 'eslint-config-next/typescript';

const eslintConfig = defineConfig([
  ...nextVitals,
  ...nextTs,
  // Override default ignores of eslint-config-next.
  globalIgnores([
    // Default ignores of eslint-config-next:
    '.next/**',
    'out/**',
    'build/**',
    'next-env.d.ts',
    // Additional ignores:
    '*.config.js',
    '*.config.mjs',
    'public/**',
    'coverage/**',
    'storybook-static/**',
  ]),
  // Prettier integration - must be last to override other configs
  prettierConfig,
  {
    // eslint-config-next only registers the react-hooks/jsx-a11y/@typescript-eslint
    // plugins for code files; without a matching `files` glob these rules would
    // also apply to generated artifacts (e.g. __tests__/__snapshots__/*.snap),
    // where ESLint cannot resolve the plugins.
    files: ['**/*.{js,jsx,mjs,ts,tsx,mts,cts}'],
    plugins: {
      prettier,
    },
    rules: {
      'prettier/prettier': 'error',
      // React hooks rules
      'react-hooks/rules-of-hooks': 'error',
      'react-hooks/exhaustive-deps': 'warn',
      // React Compiler readiness rules (bundled as "error" by eslint-config-next's
      // core-web-vitals since the Next 16 upgrade). They flag long-standing, correct
      // patterns for syncing client-only state (browser APIs, localStorage, sockets)
      // across ~50 existing files. Downgraded to warn until those are migrated
      // incrementally; genuine bugs found while triaging were fixed directly instead.
      'react-hooks/set-state-in-effect': 'warn',
      'react-hooks/purity': 'warn',
      'react-hooks/refs': 'warn',
      'react-hooks/preserve-manual-memoization': 'warn',
      // Accessibility rules
      'jsx-a11y/alt-text': 'error',
      'jsx-a11y/anchor-is-valid': 'error',
      'jsx-a11y/aria-props': 'error',
      'jsx-a11y/aria-proptypes': 'error',
      'jsx-a11y/aria-unsupported-elements': 'error',
      'jsx-a11y/role-has-required-aria-props': 'error',
      'jsx-a11y/role-supports-aria-props': 'error',
      // TypeScript rules
      '@typescript-eslint/no-unused-vars': [
        'error',
        {
          argsIgnorePattern: '^_',
          varsIgnorePattern: '^_',
        },
      ],
      '@typescript-eslint/no-explicit-any': 'warn',
      '@typescript-eslint/explicit-function-return-type': 'off',
      '@typescript-eslint/explicit-module-boundary-types': 'off',
      // General best practices
      'no-console': ['error', { allow: ['warn', 'error'] }],
      'prefer-const': 'error',
      'no-var': 'error',
    },
  },
  // Allow `any` in tests temporarily to unblock commits; replace with proper
  // typings later as a follow-up task.
  {
    files: ['**/__tests__/**', '**/*.test.*', '**/*.spec.*'],
    rules: {
      '@typescript-eslint/no-explicit-any': 'off',
      '@typescript-eslint/no-unused-vars': 'off',
    },
  },
  ...storybook.configs['flat/recommended'],
]);

export default eslintConfig;