eslint.config.ts

import js from '@eslint/js';
import type { Rule } from 'eslint';
import reactHooks from 'eslint-plugin-react-hooks';
import globals from 'globals';
import tseslint from 'typescript-eslint';

// Forward guard: only src/index.ts may be named index.* . The public barrel is the single allowed index filename; every other module gets a descriptive name so imports stay self-documenting and a stray index.ts never silently becomes a package entry point. Today only src/index.ts matches among .ts/.js files (the .tsx screens are outside the regex's scope), so this flags nothing yet -- it exists to prevent regressions.
const noNonBarrelIndexRule: Rule.RuleModule = {
  meta: {
    type: 'problem',
    schema: [],
    messages: {
      barrel:
        'Only src/index.ts may be named index.* (the public convenience barrel); give any other module a descriptive filename.',
    },
  },
  create(context) {
    const filename = context.filename;
    const lastSlash = filename.lastIndexOf('/');
    const basename = lastSlash >= 0 ? filename.slice(lastSlash + 1) : filename;
    if (!/^index\.[cm]?[tj]s$/.test(basename)) return {};
    if (filename.endsWith('/src/index.ts')) return {};
    return {
      Program(node) {
        context.report({ node, messageId: 'barrel' });
      },
    };
  },
};

export default tseslint.config(
  {
    // test/smoke.test.mjs spawns the built dist/cli.js, deliberately outside tsconfig's "src" program (it tests build output).
    ignores: ['dist', 'coverage', 'node_modules', 'test'],
  },
  {
    // Pin the TSConfig root so the parser isn't confused by stray tsconfig.json files elsewhere in the tree. Required because lint-staged runs eslint at commit time.
    //
    // `projectService` (global -- no `files` filter) powers the type-checked rules below; it must apply to every matched file or the type-checked configs crash on files outside the program.
    languageOptions: {
      parserOptions: { projectService: true, tsconfigRootDir: import.meta.dirname },
      globals: { ...globals.node },
    },
  },
  js.configs.recommended,
  ...tseslint.configs.recommended,
  // Type-checked tier: catches floating promises, misused async handlers, unsafe `any`, and invalid template expressions. Requires the `projectService` parser option set above.
  ...tseslint.configs.recommendedTypeChecked,
  ...tseslint.configs.stylisticTypeChecked,
  {
    // React Hooks correctness (rules-of-hooks, exhaustive-deps) for the Ink TUI's .tsx files -- the only React code anywhere in this repo family.
    files: ['src/tui/**/*.tsx'],
    plugins: { 'react-hooks': reactHooks },
    rules: reactHooks.configs.recommended.rules,
  },
  {
    // No inline eslint-disable / config comments anywhere -- an exception belongs in this file, scoped to the file or line it actually applies to, not hidden in the source it's disabling a rule for.
    linterOptions: { noInlineConfig: true },
  },
  {
    rules: {
      // No type assertions anywhere: narrow with a guard or parse with Zod instead.
      '@typescript-eslint/consistent-type-assertions': ['error', { assertionStyle: 'never' }],
      '@typescript-eslint/consistent-type-imports': ['error', { fixStyle: 'inline-type-imports' }],
    },
  },
  {
    // A no-op arrow function is a standard, harmless way to stand in for a callback prop (onSubmit, onCancel, ...) a given test case never exercises -- flagging every one of these as an error would just push authors toward padding each with a pointless comment body instead. Scoped to test files only: production code has no legitimate reason for an empty function body.
    files: ['**/*.test.ts', '**/*.test.tsx'],
    rules: {
      '@typescript-eslint/no-empty-function': ['error', { allow: ['arrowFunctions', 'asyncFunctions'] }],
    },
  },
  {
    plugins: { local: { rules: { 'no-non-barrel-index': noNonBarrelIndexRule } } },
    rules: { 'local/no-non-barrel-index': 'error' },
  },
);