.eslintrc.js

module.exports = {
  parserOptions: {
    ecmaVersion: 2018,
  },
  env: {
    es6: true,
    node: true,
    mocha: true,
  },
  root: true,
  extends: 'eslint:recommended',
  rules: {
    'array-bracket-spacing': [ 'error', 'always' ],
    'array-callback-return': 'error',
    'arrow-parens': 'error',
    'arrow-spacing': 'error',
    'block-spacing': 'error',
    'brace-style': [ 'error', '1tbs', { allowSingleLine: false } ],
    'comma-dangle': [ 'error', {
      arrays: 'always-multiline',
      objects: 'always-multiline',
      imports: 'always-multiline',
      exports: 'always-multiline',
      functions: 'never',
    } ],
    'comma-spacing': 'error',
    'comma-style': 'error',
    'curly': 'error',
    'dot-notation': 'error',
    'eol-last': 'error',
    'eqeqeq': [ 'error', 'always' ],
    'func-call-spacing': 'error',
    'id-length': 'error',
    'indent': [ 'error', 2, { SwitchCase: 1 } ],
    'key-spacing': 'error',
    'keyword-spacing': 'error',
    'linebreak-style': 'error',
    'no-array-constructor': 'error',
    'no-else-return': 'error',
    'no-eval': 'error',
    'no-multi-spaces': 'error',
    'no-multiple-empty-lines': [ 'error', { max: 2, maxEOF: 1, maxBOF: 1 } ],
    'no-new-object': 'error',
    'no-param-reassign': 'error',
    'no-plusplus': 'error',
    'no-restricted-globals': [ 'error', 'isNaN', 'isFinite' ],
    'no-spaced-func': 'error',
    'no-trailing-spaces': 'error',
    'no-underscore-dangle': [ 'error', { allowAfterThis: true } ],
    'no-var': 'error',
    'object-curly-spacing': [ 'error', 'always' ],
    'operator-linebreak': [ 'error', 'before' ],
    'prefer-const': 'error',
    'prefer-rest-params': 'error',
    'quote-props': [ 'error', 'consistent-as-needed' ],
    'quotes': [ 'error', 'single', {
      avoidEscape: true,
    } ],
    'radix': 'error',
    'rest-spread-spacing': 'error',
    'semi': [ 'error', 'always' ],
    'space-before-blocks': 'error',
    'space-in-parens': 'error',
    'space-infix-ops': 'error',
    'spaced-comment': [ 'error', 'always', { block: { balanced: true } } ],
  },
};