.eslintrc.yml

extends:
  - eslint:recommended
  - plugin:eslint-comments/recommended

parser: '@typescript-eslint/parser'
parserOptions:
  ecmaVersion: 2017
  sourceType: module
  jsx: true

plugins:
  - '@typescript-eslint'
  - eslint-comments
  - import
  - jest

settings:
  import/resolver:
    node:
      extensions:
        - .js
        - .jsx
        - .ts
        - .tsx
  import/parsers:
    typescript-eslint-parser:
      - .ts
      - .tsx

env:
  es6: true

rules:
  # http://eslint.org/docs/rules/

  # Possible Errors

  for-direction: error
  getter-return: error
  no-prototype-builtins: error
  no-undef: off # enforced by TypeScript
  no-unused-vars: off # enforced by TypeScript
  no-redeclare: off # enforced by TypeScript

  # Best Practices

  class-methods-use-this: error
  curly: [error, multi-line]
  dot-location: [error, property]
  eqeqeq: [error, allow-null]
  no-eval: error
  no-extend-native: error
  no-floating-decimal: error
  no-implied-eval: error
  no-labels: error
  no-lone-blocks: error
  no-new-func: error
  no-new-wrappers: error
  no-octal-escape: error
  no-proto: error
  no-return-await: error
  no-self-compare: error
  no-sequences: error
  no-unmodified-loop-condition: error
  no-unused-expressions: error
  no-useless-call: error
  no-useless-concat: error
  no-useless-return: error
  no-void: error
  no-with: error
  radix: [error, as-needed]
  wrap-iife: [error, outside]
  yoda: error

  # Variables

  no-catch-shadow: error
  no-label-var: error
  no-shadow: error
  no-shadow-restricted-names: error
  no-undef-init: error

  # Node.js and CommonJS

  handle-callback-err: [error, "^.*(e|E)rr(or)?"]
  no-mixed-requires: error
  no-new-require: error
  no-path-concat: error

  # Stylistic Issues

  array-bracket-spacing: error
  block-spacing: error
  brace-style: [error, 1tbs]
  camelcase: error
  comma-dangle: [error, {
    arrays: always-multiline,
    objects: always-multiline,
    imports: always-multiline,
    exports: always-multiline,
    functions: only-multiline,
  }]
  comma-spacing: error
  comma-style: error
  computed-property-spacing: error
  eol-last: error
  func-call-spacing: error
  func-names: [error, as-needed]
  func-style: [error, declaration, { allowArrowFunctions: true }]
  id-blacklist: [error, e, err, cb, fn]
  indent: [error, 2, { SwitchCase: 1 }]
  jsx-quotes: [error, prefer-single]
  key-spacing: [error, { mode: minimum }]
  keyword-spacing: error
  linebreak-style: error
  lines-between-class-members: [error, always, { exceptAfterSingleLine: true }]
  max-len: [error, { code: 140, comments: 80, tabWidth: 2, ignoreUrls: true }]
  new-cap: error
  newline-per-chained-call: [error, { ignoreChainWithDepth: 3 }]
  no-array-constructor: error
  no-bitwise: error
  no-lonely-if: error
  no-mixed-operators: error
  no-multiple-empty-lines: [error, { max: 1 }]
  no-new-object: error
  no-tabs: error
  no-trailing-spaces: error
  no-unneeded-ternary: error
  no-whitespace-before-property: error
  nonblock-statement-body-position: error
  object-curly-newline: [error, { consistent: true }]
  object-curly-spacing: [error, always]
  operator-assignment: error
  operator-linebreak: [error, before, { overrides: { '&&': after, '||': after } }]
  quotes: [error, single, { allowTemplateLiterals: true }]
  semi: error
  semi-spacing: error
  semi-style: error
  space-before-blocks: [error, always]
  space-before-function-paren: [error, never]
  space-in-parens: error
  # Until https://github.com/eslint/typescript-eslint-parser/issues/449
  # space-infix-ops: [error, { int32Hint: true }]
  space-unary-ops: [error, { words: true, nonwords: false }]
  spaced-comment: error
  switch-colon-spacing: error
  template-tag-spacing: error
  unicode-bom: error

  # ES2015+

  arrow-parens: [error, as-needed, { requireForBlockBody: true }]
  arrow-spacing: error
  generator-star-spacing: error
  no-confusing-arrow: error
  no-dupe-class-members: off # Enforced by TypeScript
  no-var: error
  object-shorthand: error
  prefer-arrow-callback: [error, { allowNamedFunctions: true }]
  prefer-const: error
  prefer-destructuring: [error, { array: false }]
  prefer-numeric-literals: error
  prefer-rest-params: error
  prefer-spread: error
  prefer-template: error
  rest-spread-spacing: error
  symbol-description: error
  template-curly-spacing: error
  yield-star-spacing: error

  # https://github.com/benmosher/eslint-plugin-import#rules

  # Static Analysis:
  import/no-unresolved: [error, { caseSensitive: true, commonjs: true, amd: true }]
  # TODO: Figure out why some types aren't being treated as exports
  # import/named: error
  import/default: error
  import/namespace: error
  import/no-absolute-path: error
  import/no-dynamic-require: error
  import/no-self-import: error

  # Helpful Warnings
  # TODO: Until it has TypeScript support…
  # import/export: error
  import/no-deprecated: error
  import/no-extraneous-dependencies: [error, { devDependencies: false }]
  import/no-mutable-exports: error
  import/no-useless-path-segments: error

  # Module Systems
  import/no-commonjs: error
  import/no-amd: error
  import/no-nodejs-modules: error

  # Style Guide
  # TODO: Until `import name = require('thing');` is supported
  # import/first: error
  import/no-duplicates: error
  import/extensions: [error, never]
  import/order: [error, {
    groups: [[builtin, external], [internal], [parent], [sibling, index]],
    newlines-between: always,
  }]
  import/no-default-export: error

  # https://github.com/nzakas/eslint-plugin-typescript#supported-rules

  '@typescript-eslint/adjacent-overload-signatures': error
  '@typescript-eslint/member-delimiter-style': [error, {
    overrides: {
      typeLiteral: {
        multiline: { delimiter: comma, requireLast: true },
        singleline: { delimiter: comma, requireLast: false }
      }
    }
  }]
  '@typescript-eslint/naming-convention': [
    error,
    { selector: typeLike, format: [PascalCase] },
    { selector: memberLike, modifiers: [private], format: [camelCase], leadingUnderscore: require },
    { selector: interface, format: [PascalCase], custom: { regex: '^I[A-Z]', match: false } }
  ]
  '@typescript-eslint/consistent-type-assertions': error
  '@typescript-eslint/triple-slash-reference': [error, { path: never, types: never, lib: never }]
  '@typescript-eslint/type-annotation-spacing': error

  # https://github.com/mysticatea/eslint-plugin-eslint-comments#rules

  eslint-comments/no-use: [error, { allow: [eslint-disable-line, eslint-disable-next-line] }]

  # https://github.com/jest-community/eslint-plugin-jest#rules

  jest/consistent-test-it: [error, { fn: it }]
  # TODO: https://github.com/jest-community/eslint-plugin-jest/issues/76
  # jest/lowercase-name: error
  jest/no-focused-tests: error
  jest/no-identical-title: error
  jest/no-test-prefixes: error
  jest/valid-describe: error