bump to eslint@4

4.x changes ship list

Engine

• support node >= 6 only (npm >= 3)

Dependencies

• drop unnecessary dependencies and peerDenpendencies like eslint-plugin-react, add them as optionalDependencies
• bump up version of eslint as 4.1.1
• add eslint-import-resolver-webpack, eslint-plugin-vue as optionalDependency

Features

• better support vuejs rules using eslint-plugin-vue
• support no framework generic frontend config as aftership/frontend

Docs

• v3 to v4 upgrade guide
• update why-we-chose-those-rules
• update readme.md to indicate how to use in react projects
• update readme.md to indicate how to use in vue projects

Rules:

Errors:

• no-else-return: 'error'
• no-loop-func: 'error'
• no-unused-vars: ['error', {vars: 'all', args: 'after-used', ignoreRestSiblings: true}]
• no-throw-literal: 'error'
• no-path-concat: 'error'
• indent: <default as eslint default>
• no-lonely-if: 'error'
• prefer-const: 'error'
• prefer-spread: 'error'
• prefer-rest-params: 'error'
• react/forbid-prop-types: ['error', {forbid: ['any', 'array']}]
• react/jsx-no-bind: 'react/jsx-no-bind': ['error', {ignoreRefs: true, allowArrowFunctions: true, allowBind: false}]
• react/require-default-pros: 'error'
• vue: <enabled all rules there>

Warnings:

• max-params: ['warning', 4]
• max-lines: ['warning', {max: 400, skipBlankLines: true, skipComments: true}]
• prefer-destructing: ['warning', {array: true, object: true}, {enforceForRenamedProperties: false}]
• return-yield: 'warning'
• react/no-danger: 'warn'