.eslintrc.js

const { join } = require(`path`)

const srcDir = join(__dirname, `src`)

module.exports = {
  root: true,

  env: {
    es6: true,
    node: true,
    browser: true,
    jest: true
  },

  plugins: [
    `import`, // https://github.com/benmosher/eslint-plugin-import
    `jest`, // https://github.com/jest-community/eslint-plugin-jest
    `promise`, // https://github.com/xjamundx/eslint-plugin-promise
    `vue` // https://github.com/vuejs/eslint-plugin-vue
  ],

  extends: [
    `plugin:jest/recommended`,
    'plugin:vue/essential',
    `plugin:vue/recommended`
  ],

  settings: {
    polyfills: [`fetch`, `Promise`]
  },

  parser: `vue-eslint-parser`,

  parserOptions: {
    parser: 'babel-eslint',
    ecmaVersion: 2017,
    sourceType: 'module',
    ecmaFeatures: {
      arrowFunctions: true,
      blockBindings: true,
      classes: true,
      defaultParams: true,
      destructuring: true,
      forOf: true,
      generators: false,
      modules: true,
      objectLiteralComputedProperties: true,
      objectLiteralDuplicateProperties: false,
      objectLiteralShorthandMethods: true,
      objectLiteralShorthandProperties: true,
      spread: true,
      superInFunctions: true,
      templateStrings: true,
      jsx: true
    }
  },

  rules: {
    'for-direction': 2,
    'no-await-in-loop'                          : 2,
    'no-compare-neg-zero'                       : 2,
    'no-cond-assign'                            : [2, 'always'],
    'no-console'                                : process.env.NODE_ENV === 'production' ? 'error' : 'off',
    'no-constant-condition'                     : 1,
    'no-control-regex'                          : 2,
    'no-debugger'                               : process.env.NODE_ENV === 'production' ? 'error' : 'off',
    'no-dupe-args'                              : 2,
    'no-dupe-keys'                              : 2,
    'no-duplicate-case'                         : 2,
    'no-empty'                                  : 2,
    'no-empty-character-class'                  : 2,
    'no-ex-assign'                              : 2,
    'no-extra-boolean-cast'                     : 2,
    'no-extra-parens'                           : [2, 'functions'],
    'no-extra-semi'                             : 2,
    'no-func-assign'                            : 2,
    'no-inner-declarations'                     : 2,
    'no-invalid-regexp'                         : 2,
    'no-irregular-whitespace'                   : 2,
    'no-obj-calls'                              : 2,
    'no-prototype-builtins'                     : 2,
    'no-regex-spaces'                           : 2,
    'no-sparse-arrays'                          : 2,
    'no-template-curly-in-string'               : 2,
    'no-unexpected-multiline'                   : 0,
    'no-unreachable'                            : 2,
    'no-unsafe-finally'                         : 2,
    'no-unsafe-negation'                        : 2,
    'use-isnan'                                 : 2,
    'valid-jsdoc'                               : 0,
    'valid-typeof'                              : 2,

    'accessor-pairs': 2,
    'array-callback-return'                     : 1,
    'block-scoped-var'                          : 2,
    'class-methods-use-this'                    : 0,
    complexity                                  : [0, { max: 20 }],
    'consistent-return'                         : 0,
    curly                                       : [2, 'multi-line'],
    'default-case'                              : 2,
    'dot-location'                              : [2, 'property'],
    'dot-notation'                              : [2, { allowKeywords: true }],
    eqeqeq                                      : [2, 'smart'],
    'guard-for-in'                              : 2,
    'no-alert'                                  : 2,
    'no-caller'                                 : 2,
    'no-case-declarations'                      : 2,
    'no-div-regex'                              : 2,
    'no-else-return'                            : 2,
    'no-empty-function'                         : [2, { allow: ['arrowFunctions', 'constructors'] }],
    'no-empty-pattern'                          : 2,
    'no-eq-null'                                : 2,
    'no-eval'                                   : 2,
    'no-extend-native'                          : 2,
    'no-extra-bind'                             : 2,
    'no-extra-label'                            : 2,
    'no-fallthrough'                            : 2,
    'no-floating-decimal'                       : 2,
    'no-global-assign'                          : 2,
    'no-implicit-coercion'                      : 0,
    'no-implicit-globals'                       : 0,
    'no-implied-eval'                           : 2,
    'no-invalid-this'                           : 0,
    'no-iterator'                               : 2,
    'no-labels'                                 : 2,
    'no-lone-blocks'                            : 2,
    'no-loop-func'                              : 2,
    'no-magic-numbers'                          : 0,
    'no-multi-spaces'                           : [2, { exceptions: { Property: true, VariableDeclarator: true, ImportDeclaration: true } }],
    'no-multi-str'                              : 2,
    'no-new'                                    : 2,
    'no-new-func'                               : 2,
    'no-new-wrappers'                           : 2,
    'no-octal'                                  : 2,
    'no-octal-escape'                           : 2,
    'no-param-reassign'                         : 2,
    'no-proto'                                  : 2,
    'no-redeclare'                              : 2,
    'no-restricted-properties'                  : 0,
    'no-return-assign'                          : [2, 'always'],
    'no-return-await'                           : 2,
    'no-script-url'                             : 2,
    'no-self-assign'                            : [2, { props: true }],
    'no-self-compare'                           : 2,
    'no-sequences'                              : 2,
    'no-throw-literal'                          : 2,
    'no-unmodified-loop-condition'              : 2,
    'no-unused-expressions'                     : 0,
    'no-unused-labels'                          : 2,
    'no-useless-call'                           : 2,
    'no-useless-concat'                         : 2,
    'no-useless-escape'                         : 2,
    'no-useless-return'                         : 2,
    'no-void'                                   : 2,
    'no-warning-comments'                       : 0,
    'no-with'                                   : 2,
    'prefer-promise-reject-errors'              : 2,
    radix                                       : 2,
    'require-await'                             : 2,
    'vars-on-top'                               : 2,
    'wrap-iife'                                 : [2, 'any'],
    yoda                                        : 2,

    strict: [
      2,
      'never'
    ],

    'init-declarations': 0,
    'no-catch-shadow'                           : 0,
    'no-delete-var'                             : 2,
    'no-label-var'                              : 2,
    'no-restricted-globals'                     : 0,
    'no-shadow'                                 : 2,
    'no-shadow-restricted-names'                : 2,
    'no-undef'                                  : 2,
    'no-undef-init'                             : 2,
    'no-undefined'                              : 2,
    'no-unused-vars'                            : [2, { vars: 'local', args: 'none', argsIgnorePattern: '^_' }],
    'no-use-before-define'                      : [2, { functions: true, classes: true }],

    'callback-return': 0,
    'global-require'                            : 0,
    'handle-callback-err'                       : 2,
    'no-buffer-constructor'                     : 2,
    'no-mixed-requires'                         : 0,
    'no-new-require'                            : 2,
    'no-path-concat'                            : 0,
    'no-process-env'                            : 0,
    'no-process-exit'                           : 0,
    'no-restricted-modules'                     : 0,
    'no-sync'                                   : 0,

    'array-bracket-newline'                     : [2, { multiline: true }],
    'array-bracket-spacing'                     : 2,
    'array-element-newline'                     : 0,
    'block-spacing'                             : [2, 'always'],
    'brace-style'                               : [2, '1tbs', { allowSingleLine: true }],
    camelcase                                   : [2, { properties: 'never' }],
    'capitalized-comments'                      : 0,
    'comma-dangle'                              : [2, 'never'],
    'comma-spacing'                             : [2, { before: false, after: true }],
    'comma-style'                               : [2, 'last'],
    'computed-property-spacing'                 : 2,
    'consistent-this'                           : 0,
    'eol-last'                                  : 2,
    'func-call-spacing'                         : 2,
    'func-name-matching'                        : 0,
    'func-names'                                : 0,
    'func-style'                                : [2, 'declaration', { allowArrowFunctions: true }],
    'function-paren-newline'                    : [2, 'consistent'],
    'id-blacklist'                              : 0,
    'id-length'                                 : 0,
    'id-match'                                  : 0,
    indent                                      : [2, 2, { SwitchCase: 1 }],
    'jsx-quotes'                                : [2, 'prefer-double'],
    'key-spacing'                               : 0,
    'keyword-spacing'                           : [2, { before: true, after: true }],
    'line-comment-position'                     : 0,
    'linebreak-style'                           : 0,
    'lines-around-comment'                      : 0,
    'lines-between-class-members'               : [2, 'always', { exceptAfterSingleLine: true }],
    'max-depth'                                 : 0,
    'max-len'                                   : 0,
    'max-lines'                                 : 0,
    'max-nested-callbacks'                      : 0,
    'max-params'                                : 0,
    'max-statements'                            : 0,
    'max-statements-per-line'                   : 0,
    'multiline-comment-style'                   : 0,
    'multiline-ternary'                         : [2, 'always-multiline'],
    'new-cap'                                   : 0,
    'new-parens'                                : 2,
    'newline-per-chained-call'                  : 0,
    'no-array-constructor'                      : 0,
    'no-bitwise'                                : [2, { allow: ['~'] }],
    'no-continue'                               : 2,
    'no-inline-comments'                        : 0,
    'no-lonely-if'                              : 2,
    'no-mixed-operators'                        : 0,
    'no-mixed-spaces-and-tabs'                  : [2, 'smart-tabs'],
    'no-multi-assign'                           : 2,
    'no-multiple-empty-lines'                   : [2, { max: 2 }],
    'no-negated-condition'                      : 2,
    'no-nested-ternary'                         : 0,
    'no-new-object'                             : 2,
    'no-plusplus'                               : 0,
    'no-restricted-syntax'                      : 0,
    'no-tabs'                                   : 0,
    'no-ternary'                                : 0,
    'no-trailing-spaces'                        : 2,
    'no-underscore-dangle'                      : 0,
    'no-unneeded-ternary'                       : 2,
    'no-whitespace-before-property'             : 2,
    'nonblock-statement-body-position'          : 0,
    'object-curly-newline'                      : [2, { ObjectExpression: { consistent: true }, ObjectPattern: { consistent: true } }],
    'object-curly-spacing'                      : [2, 'always'],
    'object-property-newline'                   : [2, { allowMultiplePropertiesPerLine: true }],
    'one-var'                                   : [2, 'never'],
    'one-var-declaration-per-line'              : [2, 'always'],
    'operator-assignment'                       : [2, 'always'],
    'operator-linebreak'                        : [2, 'before', { overrides: { '&&': 'ignore', '=': 'ignore' } }],
    'padded-blocks'                             : [2, 'never'],
    'padding-line-between-statements'           : 0,
    'quote-props'                               : [2, 'consistent-as-needed'],
    quotes                                    : [2, 'backtick', 'avoid-escape'],
    'require-jsdoc'                             : 0,
    semi                                      : [2, 'never'],
    'semi-spacing'                              : [2, { before: false, after: true }],
    'semi-style'                                : [2, 'last'],
    'sprt-keys'                                 : 0,
    'sort-vars'                                 : 0,
    'space-before-blocks'                       : 2,
    'space-before-function-paren'               : [2, { anonymous: 'never', named: 'never', asyncArrow: 'always' }],
    'space-in-parens'                           : [2, 'never'],
    'space-infix-ops'                           : 2,
    'space-unary-ops'                           : [2, { words: true, nonwords: false }],
    'spaced-comment'                            : [0, 'always', { plugins: ['react'], exceptions: ['*'], markers: ['*'] }],
    'switch-colon-spacing'                      : [2, { before: false, after: true }],
    'template-tag-spacing'                      : [2, 'never'],
    'unicode-bom'                               : 0,
    'wrap-regex'                                : 2,

    'arrow-body-style': [
      2,
      'as-needed'
    ],
    'arrow-parens'                              : [2, 'as-needed'],
    'arrow-spacing'                             : [2, { before: true, after: true }],
    'constructor-super'                         : 0,
    'generator-star-spacing'                    : [2, { before: true, after: false }],
    'no-class-assign'                           : 2,
    'no-confusing-arrow'                        : [2, { allowParens: true }],
    'no-const-assign'                           : 2,
    'no-dupe-class-members'                     : 2,
    'no-duplicate-imports'                      : 2,
    'no-new-symbol'                             : 2,
    'no-restricted-imports'                     : 0,
    'no-this-before-super'                      : 2,
    'no-useless-computed-key'                   : 2,
    'no-useless-constructor'                    : 2,
    'no-useless-rename'                         : 2,
    'no-var'                                    : 2,
    'object-shorthand'                          : [2, 'properties'],
    'prefer-arrow-callback'                     : 2,
    'prefer-const'                              : 0,
    'prefer-destructuring'                      : 0,
    'prefer-numeric-literals'                   : 2,
    'prefer-rest-params'                        : 2,
    'prefer-spread'                             : 2,
    'prefer-template'                           : 2,
    'require-yield'                             : 2,
    'rest-spread-spacing'                       : [2, 'never'],
    'sort-imports'                              : 0,
    'symbol-description'                        : 2,
    'template-curly-spacing'                    : [2, 'never'],
    'yield-star-spacing'                        : [2, { before: false, after: true }],

    'import/no-unresolved': [
      2,
      {
        commonjs: true,
        amd: true
      }
    ],
    'import/named'                              : 2,
    'import/default'                            : 2,
    'import/no-webpack-loader-syntax'           : 2,
    'import/export'                             : 2,
    'import/no-deprecated'                      : 2,
    'import/no-mutable-exports'                 : 2,
    'import/no-duplicates'                      : 2,
    'import/no-namespace'                       : 0,
    'import/newline-after-import'               : 2,
    'import/order'                              : [2, { 'newlines-between': 'never', groups: ['builtin', ['internal', 'external'], ['parent', 'sibling'], 'index'] }],

    'promise/catch-or-return': [
      2,
      {
        terminationMethod: [
          'catch',
          'finally'
        ]
      }
    ],
    'promise/always-return'                     : 2,
    'promise/no-return-wrap'                    : 2,
    'promise/param-names'                       : 2,
    'promise/prefer-await-to-then'              : 2,
    'promise/prefer-await-to-callbacks'         : 2,
  }
}