.eslintrc.js

module.exports = {
  'globals': {
    'Promise': true
  },
  'env': {
    'mocha': true,
    'browser': true,
    'node': true,
    'jquery': true
  },
  'parser': 'babel-eslint',
  'plugins': [
    'babel'
  ],
  'rules': {
    // 0 = off, 1 = warn, 2 = error

    // Possible Errors
    'for-direction': 'off',
    'getter-return': 'off',
    'no-await-in-loop': 'off',
    'no-compare-neg-zero': 'warn',
    'no-cond-assign': ['error', 'except-parens'],
    'no-console': 'off',
    'no-constant-condition': 'warn',
    'no-control-regex': 'warn',
    'no-debugger': 'off',
    'no-dupe-args': 'error',
    'no-dupe-keys': 'error',
    'no-duplicate-case': 'error',
    'no-empty': 'warn',
    'no-empty-character-class': 'error',
    'no-ex-assign': 'error',
    'no-extra-boolean-cast': 'warn',
    'no-extra-parens': 'off',
    'no-extra-semi': 'warn',
    'no-func-assign': 'error',
    'no-inner-declarations': ['warn', 'functions'],
    'no-invalid-regexp': 'error',
    'no-irregular-whitespace': 'off',
    'no-obj-calls': 'warn',
    'no-prototype-builtins': 'warn',
    'no-regex-spaces': 'warn',
    'no-sparse-arrays': 'error',
    'no-template-curly-in-string': 'error',
    'no-unexpected-multiline': 'warn',
    'no-unreachable': 'error',
    'no-unsafe-finally': 'error',
    'no-unsafe-negation': 'error',
    'use-isnan': 'warn',
    'valid-jsdoc': 'off',
    'valid-typeof': 'error',

    // Best Practices
    'accessor-pairs': 'warn',
    'array-callback-return': 'warn',
    'block-scoped-var': 'off', // see Babel section
    'class-methods-use-this': 'warn',
    'complexity': ['warn', 14],
    'consistent-return': 'warn',
    'curly': ['error', 'all'],
    'default-case': 'warn',
    'dot-location': ['warn', 'property'],
    'dot-notation': ['warn', { allowKeywords: true }], // allowPattern: regex
    'eqeqeq': 'error',
    'guard-for-in': 'warn',
    'no-alert': 'error',
    'no-caller': 'off',
    'no-case-declarations': 'warn',
    'no-div-regex': 'warn',
    'no-else-return': 'warn',
    'no-empty-function': 'warn',
    'no-empty-pattern': 'warn',
    'no-eq-null': 'off',
    'no-eval': 'warn',
    'no-extend-native': 'error',
    'no-extra-bind': 'warn',
    'no-extra-label': 'error',
    'no-fallthrough': 'off',
    'no-floating-decimal': 'off',
    'no-global-assign': 'error',
    'no-implicit-coercion': 'warn',
    'no-implicit-globals': 'warn',
    'no-implied-eval': 'error',
    'no-invalid-this': 'error',
    'no-iterator': 'error',
    'no-labels': 'error',
    'no-lone-blocks': 'warn',
    'no-loop-func': 'warn',
    'no-magic-numbers': 'off',
    'no-multi-spaces': 'warn',
    'no-multi-str': 'warn',
    'no-new': 'off',
    'no-new-func': 'error',
    'no-new-wrappers': 'error',
    'no-octal': 'warn',
    'no-octal-escape':'warn',
    'no-param-reassign': 'warn',
    'no-proto': 'error',
    'no-redeclare': 'off',
    'no-restricted-properties': 'off',
    'no-return-assign': 'error',
    'no-return-await': 'warn',
    'no-script-url': 'error',
    'no-self-assign': 'error',
    'no-self-compare': 'error',
    'no-sequences': 'warn',
    'no-throw-literal': 'error',
    'no-unmodified-loop-condition': 'error',
    'no-unused-expressions': 'warn',
    'no-unused-labels': 'error',
    'no-useless-call': 'warn',
    'no-useless-concat': 'warn',
    'no-useless-escape': 'warn',
    'no-useless-return': 'warn',
    'no-void': 'warn',
    'no-warning-comments': ['off', { 'terms': ['todo', 'tofix'], 'location': 'start' }],
    'no-with': 'off',
    'prefer-promise-reject-errors': 'warn',
    'radix': 'off',
    'require-await': 'warn',
    'vars-on-top': 'off',
    'wrap-iife': ['error', 'inside'],
    'yoda': ['warn', 'never'],

    // Strict Mode
    'strict': ['error', 'never'],

    // Variables
    'init-declarations': ['warn', 'always'],
    'no-catch-shadow': 'off',
    'no-delete-var': 'error',
    'no-label-var': 'warn',
    'no-restricted-globals': 'off',
    'no-shadow': 'warn',
    'no-shadow-restricted-names': 'error',
    'no-undef': 'warn',
    'no-undef-init': 'warn',
    'no-undefined': 'warn',
    'no-unused-vars': ['warn', { 'vars': 'local', 'args': 'after-used' }],
    'no-use-before-define': 'error',

    // Node.js
    'callback-return': 'error',
    'global-require': 'warn',
    'handle-callback-err': 'error',
    'no-buffer-constructor': 'warn',
    'no-mixed-requires': ['warn', { allowCall: true }],
    'no-new-require': 'warn',
    'no-path-concat': 'warn',
    'no-process-env': 'off',
    'no-process-exit': 'error',
    'no-restricted-modules': ['off', ''], // add any unwanted Node.js core modules
    'no-sync': 'error',

    // Stylistic Issues
    'array-bracket-newline': ['off', 'never'],
    'array-bracket-spacing': ['warn', 'never'],
    'array-element-newline': ['off', 'never'],
    'block-spacing': ['warn', 'always'],
    'brace-style': ['warn', '1tbs', { allowSingleLine: true }],
    'camelcase': ['warn', { properties: 'always' }],
    'capitalized-comments': 'off',
    'comma-dangle': ['warn', 'always-multiline'],
    'comma-spacing': ['warn', { before: false, after: true }],
    'comma-style': ['warn', 'last'],
    'computed-property-spacing': ['warn', 'never'],
    'consistent-this': 'off',
    'eol-last': 'warn',
    'func-call-spacing': ['warn', 'never'],
    'func-name-matching': 'off',
    'func-names': ['warn', 'always'],
    'func-style': 'off',
    'function-paren-newline': 'off',
    'id-blacklist': 'off', // [.., ..]
    'id-length': 'off',
    'id-match': 'off',
    'indent': ['warn', 2],
    'jsx-quotes': 'off',
    'key-spacing': ['warn', { beforeColon: false, afterColon: true }],
    'keyword-spacing': ['warn', { before: true, after: true }],
    'line-comment-position': 'off',
    'linebreak-style': 'off',
    'lines-around-comment': 'off',
    'max-depth': ['warn', { max: 6 }],
    'max-len': ['warn', { code: 120 }],
    'max-lines': 'off',
    'max-nested-callbacks': ['warn', { max: 6 }],
    'max-params': 'off',
    'max-statements': 'off',
    'max-statements-per-line': 'off',
    'multiline-ternary': 'off',
    'new-cap': 'off', // see Babel section
    'new-parens': 'error',
    'newline-per-chained-call': ['warn', { ignoreChainWithDepth: 2 }],
    'no-array-constructor': 'warn',
    'no-bitwise': 'warn',
    'no-continue': 'warn',
    'no-inline-comments': 'off',
    'no-lonely-if': 'warn',
    'no-mixed-operators': 'warn',
    'no-mixed-spaces-and-tabs': 'warn',
    'no-multi-assign': 'error',
    'no-multiple-empty-lines': ['warn', { 'max': 1 }],
    'no-negated-condition': 'off',
    'no-nested-ternary': 'error',
    'no-new-object': 'warn',
    'no-plusplus': ['warn', { allowForLoopAfterthoughts: true }],
    'no-restricted-syntax': 'off',
    'no-tabs': 'warn',
    'no-ternary': 'off',
    'no-trailing-spaces': 'warn',
    'no-underscore-dangle': 'warn',
    'no-unneeded-ternary': 'warn',
    'no-whitespace-before-property': 'warn',
    'nonblock-statement-body-position': 'off',
    'object-curly-newline': 'off',
    'object-curly-spacing': 'off', // see Babel section
    'object-property-newline': 'off',
    'one-var': ['warn', 'never'],
    'one-var-declaration-per-line': 'off',
    'operator-assignment': ['warn', 'never'],
    'operator-linebreak': 'off',
    'padded-blocks': ['off', 'never'],
    'padding-line-between-statements': 'off',
    'quote-props': ['warn', 'consistent-as-needed'],
    'quotes': ['warn', 'single'],
    'require-jsdoc': 'off',
    'semi': ['error', 'always'],
    'semi-spacing': ['warn', { before: false, after: true }],
    'semi-style': 'off',
    'sort-keys': 'off',
    'sort-vars': 'off',
    'space-before-blocks': ['warn', 'always'],
    'space-before-function-paren': ['warn', 'never'],
    'space-in-parens': ['warn', 'never'],
    'space-infix-ops': 'warn',
    'space-unary-ops': 'off',
    'spaced-comment': ['warn', 'always'],
    'switch-colon-spacing': ['warn', { after: true, before: false}],
    'template-tag-spacing': 'off',
    'unicode-bom': 'off',
    'wrap-regex': 'warn',

    // ECMAScript 6
    'arrow-body-style': ['warn', 'as-needed'],
    'arrow-parens': ['warn', 'as-needed'],
    'arrow-spacing': ['warn', { before: true, after: true }],
    'constructor-super': 'warn',
    'generator-star-spacing': 'off',
    'no-class-assign': 'error',
    'no-confusing-arrow': 'warn',
    'no-const-assign': 'error',
    'no-dupe-class-members': 'error',
    'no-duplicate-imports': 'warn',
    'no-new-symbol': 'warn',
    'no-restricted-imports': 'off', // [.., ..]
    'no-this-before-super': 'warn',
    'no-useless-computed-key': 'off',
    'no-useless-constructor': 'warn',
    'no-useless-rename': 'warn',
    'no-var': 'error',
    'object-shorthand': ['warn', 'properties'],
    'prefer-arrow-callback': 'warn',
    'prefer-const': 'warn',
    'prefer-destructuring': 'off',
    'prefer-numeric-literals': 'off',
    'prefer-rest-params': 'warn',
    'prefer-spread': 'warn',
    'prefer-template': 'warn',
    'require-yield': 'off',
    'rest-spread-spacing': ['warn', 'never'],
    'sort-imports': 'off',
    'symbol-description': 'warn',
    'template-curly-spacing': ['warn', 'never'],
    'yield-star-spacing': 'off',

    // Babel
    'babel/new-cap': 1,
    'babel/object-curly-spacing': [1, 'always']
  }
};