eslintconfig.cjs

module.exports = {
  rules: {
    // ECMAScript 6
    // http://eslint.org/docs/rules/#ecmascript-6
    // ------------------------------------------
    'no-cond-assign': 'error', // eslint:recommended
    'no-irregular-whitespace': 'error', // eslint:recommended
    'no-unexpected-multiline': 'error', // eslint:recommended
    'valid-jsdoc': [
      'error',
      {
        requireParamDescription: false,
        requireReturnDescription: false,
        requireReturn: false,
        prefer: {returns: 'return'},
      },
    ],

    'no-console': 'error',
    'no-constant-condition': 'error',
    'no-control-regex': 'error',
    'no-debugger': 'error',
    'no-dupe-keys': 'error',
    'no-dupe-args': 'error',
    'no-duplicate-case': 'error',
    'no-empty': 'error',
    'no-empty-character-class': 'error',
    'no-ex-assign': 'error',
    'no-extra-boolean-cast': 'error',
    'no-extra-semi': 'error',
    'no-func-assign': 'error',
    'no-inner-declarations': ['error', 'functions'],
    'no-invalid-regexp': 'error',
    'no-unsafe-negation': 'error',
    'no-obj-calls': 'error',
    'no-regex-spaces': 'error',
    'no-sparse-arrays': 'error',
    'no-unreachable': 'error',
    'use-isnan': 'error',
    'valid-typeof': 'error',

    // Best Practices
    // http://eslint.org/docs/rules/#best-practices
    // --------------------------------------------

    'guard-for-in': 'error',
    'max-nested-callbacks': ['error', {max: 3}],
    'no-caller': 'error',
    'no-extend-native': 'error',
    'no-extra-bind': 'error',
    'no-invalid-this': 'error',
    'no-multi-spaces': 'error',
    'no-multi-str': 'error',
    'no-new-wrappers': 'error',
    'no-throw-literal': 'error', // eslint:recommended
    'no-with': 'error',
    'consistent-return': 'error',
    curly: ['error', 'all'],
    eqeqeq: 'error',
    'no-alert': 'error',
    'no-eval': 'error',
    'no-fallthrough': 'error',
    'no-floating-decimal': 'error',
    'no-implied-eval': 'error',
    'no-iterator': 'error',
    'no-labels': 'error',
    'no-lone-blocks': 'error',
    'no-global-assign': 'error',
    'no-new': 'error',
    'no-new-func': 'error',
    'no-octal': 'error', // default
    'no-octal-escape': 'error',
    'no-proto': 'error',
    'no-redeclare': 'error', // default
    'no-return-assign': 'error',
    'no-script-url': 'error',
    'no-sequences': 'error',
    'no-unused-expressions': 'error',
    radix: 'error',

    // Variables
    // http://eslint.org/docs/rules/#variables
    // ---------------------------------------
    'no-unused-vars': ['error', {args: 'after-used', argsIgnorePattern: '^_'}], // check that all args are used¬
    'no-delete-var': 'error', // eslint:recommended
    'no-label-var': 'error',
    'no-shadow': 'error',
    'no-shadow-restricted-names': 'error',
    'no-undef': 'error', // default
    'no-undef-init': 'error',
    'no-undefined': 'error',

    // Node.js and CommonJS
    // http://eslint.org/docs/rules/#nodejs-and-commonjs
    // -------------------------------------------------
    'no-process-exit': 'error',

    // Stylistic Issues
    // http://eslint.org/docs/rules/#stylistic-issues
    // ----------------------------------------------
    indent: [
      'error',
      2,
      {
        SwitchCase: 1,
        // continuation indent
        VariableDeclarator: 1, // indent is multiplier * indent = 1 * 2
        MemberExpression: 2, // indent is multiplier * indent = 2 * 2
        FunctionDeclaration: {parameters: 2},
        FunctionExpression: {parameters: 2},
        CallExpression: {arguments: 2},
      },
    ],
    'block-spacing': ['error', 'always'],
    'array-bracket-spacing': ['error', 'never'],
    'brace-style': 'error',
    camelcase: 'error',
    'comma-spacing': 'error',
    'comma-style': 'error',
    'computed-property-spacing': 'error',
    'eol-last': 'error',
    'func-call-spacing': 'error',
    'key-spacing': 'error',
    'keyword-spacing': 'error',
    'linebreak-style': 'off', // check this in git
    'new-cap': 'error',
    'no-array-constructor': 'error',
    'no-mixed-spaces-and-tabs': 'error', // eslint:recommended
    'no-multiple-empty-lines': ['error', {max: 2}],
    'no-new-object': 'error',
    'no-trailing-spaces': 'error',
    'object-curly-spacing': 'error',
    'one-var': [
      'error',
      {
        var: 'never',
        let: 'never',
        const: 'never',
      },
    ],
    'padded-blocks': ['off', 'never'],
    'quote-props': ['error', 'consistent'],
    'semi-spacing': 'error',
    semi: 'error',
    'space-in-parens': ['error', 'never'],
    'space-before-blocks': 'error',
    'space-before-function-paren': ['error', {named: 'never', anonymous: 'always'}],
    'spaced-comment': ['error', 'always'],
    'unicode-bom': 'warn',
    'new-parens': 'error',
    'no-nested-ternary': 'error',
    'space-infix-ops': 'error',
    'space-unary-ops': ['error', {words: true, nonwords: false}],
    yoda: ['error', 'never'],

    'arrow-parens': ['error', 'always'],

    // parens are optional but recommended.
    // ESLint doesn't support a *consistent*
    // setting so "always" is used.
    'constructor-super': 'error', // eslint:recommended
    'generator-star-spacing': ['error', 'after'],
    'no-new-symbol': 'error', // eslint:recommended
    'no-this-before-super': 'error', // eslint:recommended
    'no-var': 'error',
    'prefer-rest-params': 'error',
    'prefer-spread': 'error',
    'rest-spread-spacing': 'error',
    'yield-star-spacing': ['error', 'after'],
    'object-shorthand': ['error', 'always', {avoidQuotes: true}],

    'comma-dangle': [
      'error',
      {
        arrays: 'always-multiline',
        objects: 'always-multiline',
        imports: 'never',
        exports: 'never',
        functions: 'never',
      },
    ],
    quotes: ['error', 'single'],
  },
};