eslint.config.cjs

const globals = require('globals');
const js = require('@eslint/js');

const {
  FlatCompat,
} = require('@eslint/eslintrc');

const compat = new FlatCompat({
   
  baseDirectory: __dirname,
  recommendedConfig: js.configs.recommended,
  allConfig: js.configs.all
});

module.exports = [...compat.extends('eslint:recommended'), {
  languageOptions: {
    globals: {
      ...globals.node,
      ...globals.commonjs,
      ...globals.jest,
    },

    ecmaVersion: 12,
    sourceType: 'commonjs',
  },

  rules: {
    'no-console': 'warn',
    'no-undef': 'error',
    semi: 'error',
    'semi-spacing': 'error',
    eqeqeq: 'warn',
    'no-invalid-this': 'error',
    'no-return-assign': 'error',

    'no-unused-expressions': ['error', {
      allowTernary: true,
    }],

    'no-useless-concat': 'error',
    'no-useless-return': 'error',
    'no-constant-condition': 'warn',

    'no-unused-vars': ['warn', {
      argsIgnorePattern: 'req|res|next|__',
    }],

    indent: ['error', 2, {
      SwitchCase: 1,
    }],

    'no-mixed-spaces-and-tabs': 'warn',
    'space-before-blocks': 'error',
    'space-in-parens': 'error',
    'space-infix-ops': 'error',
    'space-unary-ops': 'error',
    quotes: ['error', 'single'],

    'max-len': ['error', {
      code: 200,
    }],

    'max-lines': ['error', {
      max: 500,
    }],

    'keyword-spacing': 'error',
    'multiline-ternary': ['error', 'never'],
    'no-mixed-operators': 'error',

    'no-multiple-empty-lines': ['error', {
      max: 2,
      maxEOF: 1,
    }],

    'no-whitespace-before-property': 'error',
    'nonblock-statement-body-position': 'error',

    'object-property-newline': ['error', {
      allowAllPropertiesOnSameLine: true,
    }],

    'arrow-spacing': 'error',
    'no-confusing-arrow': 'error',
    'no-duplicate-imports': 'error',
    'no-var': 'error',
    'object-shorthand': 'off',
    'prefer-const': 'error',
    'prefer-template': 'warn',
  },
}];