eslint.config.js

import js from '@eslint/js';
import globals from 'globals';
import stylistic from '@stylistic/eslint-plugin';

const styleRules = {
  '@stylistic/array-bracket-spacing': [ 'error', 'always' ],
  '@stylistic/arrow-parens': [ 'error', 'as-needed' ],
  '@stylistic/arrow-spacing': [ 'error', { before: true, after: true } ],
  '@stylistic/block-spacing': [ 'error', 'always' ],
  '@stylistic/brace-style': [ 'error', '1tbs', { allowSingleLine: true } ],
  '@stylistic/comma-dangle': [ 'error', 'never' ],
  '@stylistic/comma-spacing': [ 'error' ],
  '@stylistic/computed-property-spacing': [ 'error', 'never' ],
  '@stylistic/eol-last': [ 'error', 'always' ],
  '@stylistic/function-call-spacing': [ 'error', 'never' ],
  '@stylistic/generator-star-spacing': [ 'error', { before: true, after: false } ],
  '@stylistic/indent': [ 'error', 2 ],
  '@stylistic/key-spacing': [ 'error', { afterColon: true } ],
  '@stylistic/keyword-spacing': [ 'error' ],
  '@stylistic/max-len': [ 'error', { code: 150, tabWidth: 2, comments: Infinity } ],
  '@stylistic/no-mixed-operators': [ 'error' ],
  '@stylistic/no-multi-spaces': [ 'error' ],
  '@stylistic/no-multiple-empty-lines': [ 'error', { max: 1, maxEOF: 1 } ],
  '@stylistic/no-tabs': [ 'error' ],
  '@stylistic/no-trailing-spaces': [ 'error' ],
  '@stylistic/object-curly-newline': [ 'error', { consistent: true, multiline: true } ],
  '@stylistic/object-curly-spacing': [ 'error', 'always' ],
  '@stylistic/operator-linebreak': [ 'error', 'after' ],
  '@stylistic/quote-props': [ 'error', 'as-needed' ],
  '@stylistic/quotes': [ 'error', 'single' ],
  '@stylistic/semi': [ 'error', 'always' ],
  '@stylistic/space-before-blocks': [ 'error' ],
  '@stylistic/space-before-function-paren': [ 'error', { anonymous: 'always', named: 'never', asyncArrow: 'always' } ],
  '@stylistic/space-in-parens': [ 'error', 'always', { exceptions: [ 'empty' ] } ],
  '@stylistic/space-infix-ops': [ 'error' ],
  '@stylistic/space-unary-ops': [ 'error', { words: true, nonwords: false } ]
};

const restrictedSyntax = [
  'error',
  'DebuggerStatement',
  'Eval',
  'ForInStatement',
  'LabeledStatement',
  'WithStatement',
  { selector: 'VariableDeclaration[kind="let"]', message: 'Using \'let\' is not allowed.' }
];

const lintRules = {
  camelcase: [ 'error', { properties: 'never' } ],
  'consistent-return': [ 'error', { treatUndefinedAsUnspecified: true } ],
  curly: [ 'error' ],
  eqeqeq: [ 'error' ],
  'func-names': 0,
  'global-require': [ 'error' ],
  'init-declarations': [ 'error', 'always' ],
  'no-bitwise': [ 'error', { int32Hint: true } ],
  'no-buffer-constructor': [ 'error' ],
  'no-console': 0,
  'no-nested-ternary': [ 'error' ],
  'no-param-reassign': [ 'error' ],
  'no-plusplus': 0,
  'no-regex-spaces': [ 'error' ],
  'no-restricted-syntax': restrictedSyntax,
  'no-return-await': [ 'error' ],
  'no-template-curly-in-string': 0,
  'no-undef': [ 'error' ],
  'no-underscore-dangle': 0,
  'no-unused-expressions': [ 'error' ],
  'no-unused-vars': [ 'error', { argsIgnorePattern: '^_', destructuredArrayIgnorePattern: '^_', ignoreRestSiblings: true } ],
  'no-use-before-define': [ 'error' ],
  'no-useless-catch': 0,
  'no-useless-constructor': 1,
  'no-var': [ 'error' ],
  'object-shorthand': [ 'error' ],
  'prefer-const': [ 'error' ],
  'require-atomic-updates': 0
};

export default [
  {
    ignores: [
      'dist/**',
      '@stylistic/*/coverage/**',
      'coverage/**'
    ]
  },
  js.configs.recommended,
  {
    files: [ '**/*.{js,cjs,mjs}' ],
    languageOptions: {
      ecmaVersion: 2025,
      globals: {
        ...globals.node,
        ...globals.jest
      }
    },
    plugins: {
      '@stylistic': stylistic
    },
    rules: {
      ...styleRules,
      ...lintRules
    }
  }
];