知识点
安装 ESlint
npm install -g eslint
eslint --init
根据提示安装选择需要的配置,这里我选择的是 json 格式的文件。
最后就在根目录下生成.eslintrc.json
。
配置规则
ESlint 是基于规则在检测代码的。
- env:你的脚本将要运行在什么环境中;
- globals:额外的全局变量;
- parserOptions:JavaScript 选项。
"parserOptions": {
"ecmaVersion":6,
"sourceType":"script",
"ecmaFeatures": {
"globalReturn":true,
"impliedStrict":true,
"jsx":true
}
}
rules:开启规则和发生错误时报告的等级,规则的错误等级有三种:
- 0 或’off’:关闭规则。
- 1 或’warn’:打开规则,并且作为一个警告(并不会导致检查不通过)。
- 2 或’error’:打开规则,并且作为一个错误(退出码为1,检查不通过)。
'rules': {
"no-cond-assign": 2,
"no-console": 0,
"no-constant-condition": 2,
"no-control-regex": 2,
"comma-dangle": [1, "always-multiline"],
"no-debugger": 2,
"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": 0,
"no-extra-semi": 2,
"no-func-assign": 2,
"no-inner-declarations": [2, "functions"],
"no-invalid-regexp": 2,
"no-irregular-whitespace": 2,
"no-negated-in-lhs": 2,
"no-obj-calls": 2,
"no-prototype-builtins": 0,
"no-regex-spaces": 2,
"no-sparse-arrays": 2,
"no-unexpected-multiline": 2,
"no-unreachable": 2,
"use-isnan": 2,
"valid-jsdoc": 1,
"valid-typeof": 2,
"accessor-pairs": 2,
"array-callback-return": 0,
"block-scoped-var": 0,
"complexity": [2, 9],
"consistent-return": 0,
"curly": [2, "all"],
"default-case": 2,
"dot-location": [2, "property"],
"dot-notation": [2, {"allowKeywords": false}],
"eqeqeq": [2, "allow-null"],
"guard-for-in": 2,
"no-alert": 0,
"no-caller": 2,
"no-case-declarations": 2,
"no-div-regex": 2,
"no-else-return": 0,
"no-empty-function": 2,
"no-empty-pattern": 2,
"no-eq-null": 1,
"no-eval": 2,
"no-extend-native": 2,
"no-extra-bind": 2,
"no-extra-label:": 0,
"no-fallthrough": 2,
"no-floating-decimal": 2,
"no-implicit-coercion": 0,
"no-implicit-globals": 1,
"no-implied-eval": 2,
"no-invalid-this": 0,
"no-iterator": 2,
"no-labels": 2,
"no-lone-blocks": 2,
"no-loop-func": 1,
"no-magic-numbers":[1, {"ignore": [0, -1, 1] }],
"no-multi-spaces": 2,
"no-multi-str": 2,
"no-native-reassign": 2,
"no-new": 2,
"no-new-func": 0,
"no-new-wrappers": 2,
"no-octal": 2,
"no-octal-escape": 2,
"no-param-reassign": 0,
"no-proto": 2,
"no-redeclare": 2,
"no-return-assign": 0,
"no-script-url": 0,
"no-self-assign": 2,
"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": 0,
"no-void": 0,
"no-warning-comments": 0,
"no-with": 2,
"radix": 2,
"vars-on-top": 0,
"wrap-iife": [2, "any"],
"yoda": [2, "never"],
"strict": 0,
"init-declarations": 0,
"no-catch-shadow": 0,
"no-delete-var": 2,
"no-label-var": 2,
"no-restricted-globals": 0,
"no-shadow": 0,
"no-shadow-restricted-names": 2,
"no-undef": 2,
"no-undef-init": 2,
"no-undefined": 0,
"no-unused-vars": [2, {"vars": "all", "args": "none"}],
"no-use-before-define": 0,
"callback-return": 0,
"global-require": 1,
"handle-callback-err": [2, "^(err|error)$"],
"no-mixed-requires": 0,
"no-new-require": 2,
"no-path-concat": 0,
"no-process-env": 0,
"no-process-exit": 0,
"no-sync": 0,
"array-bracket-spacing": [2, "never"],
"block-spacing":[1, "never"],
"brace-style": [2, "1tbs", {"allowSingleLine": true}],
"camelcase": 2,
"comma-spacing": [2, {"before": false, "after": true}],
"comma-style": [2, "last"],
"computed-property-spacing": [2, "never"],
"consistent-this": [1, "that"],
"func-names": 0,
"eol-last": 2,
"indent": [2, 4, {"SwitchCase": 1}],
"key-spacing": [2, {"beforeColon": false, "afterColon": true}],
"linebreak-style": [1, "unix"],
"lines-around-comment": [1, {"beforeBlockComment": true}],
"func-style": 0,
"max-nested-callbacks": [1, 5],
"id-blacklist": 0,
"id-length": 0,
"id-match": 0,
"jsx-quotes": 0,
"keyword-spacing": 2,
"max-len":[1, 200],
"max-lines": 0,
"max-params":[1, 7],
"max-statements":[1, 200],
"max-statements-per-line": 0,
"new-cap": [2, {"newIsCap": true, "capIsNew": false}],
"new-parens": 2,
"newline-after-var": 0,
"no-array-constructor": 2,
"no-bitwise": 0,
"newline-before-return": 0,
"newline-per-chained-call": 1,
"no-continue": 0,
"no-inline-comments": 0,
"no-lonely-if": 0,
"no-mixed-operators": 0,
"no-mixed-spaces-and-tabs": 2,
"no-multiple-empty-lines": [2, {"max": 2}],
"no-negated-condition": 0,
"no-nested-ternary": 0,
"no-new-object": 2,
"no-plusplus": 0,
"no-restricted-syntax": 0,
"no-spaced-func": 2,
"no-ternary": 0,
"no-trailing-spaces": 2,
"no-underscore-dangle": 0,
"no-unneeded-ternary": 2,
"no-whitespace-before-property": 0,
"object-curly-newline": 0,
"object-curly-spacing": 0,
"object-property-newline": 0,
"one-var": [2, {"initialized": "never"}],
"one-var-declaration-per-line": 0,
"operator-assignment": 0,
"operator-linebreak": [2, "after", {"overrides": {"?":"before", ":": "before"}}],
"padded-blocks": 0,
"quote-props": 0,
"quotes": [2, "single", "avoid-escape"],
"require-jsdoc": 1,
"semi": [2, "always"],
"semi-spacing": 0,
"sort-vars": 0,
"space-before-blocks": [2, "always"],
"space-before-function-paren": [2, "always"],
"space-in-parens": [2, "never"],
"space-infix-ops": 2,
"space-unary-ops": [2, {"words": true, "nonwords": false}],
"spaced-comment": [2, "always", {"markers": ["global", "globals", "eslint", "eslint-disable", "*package","!"] }],
"unicode-bom": 0,
"wrap-regex": 0,
"arrow-body-style": 2,
"arrow-parens": 2,
"arrow-spacing":[2, {"before": true, "after": true}],
"constructor-super": 0,
"generator-star-spacing": [2, {"before": true, "after": true}],
"no-class-assign": 2,
"no-confusing-arrow": 0,
"no-const-assign": 2,
"no-dupe-class-members": 2,
"no-duplicate-imports": 0,
"no-new-symbol": 2,
"no-restricted-imports": 0,
"no-this-before-super": 2,
"no-useless-computed-key": 0,
"no-var": 0,
"object-shorthand": 0,
"prefer-arrow-callback": 0,
"prefer-const": 0,
"prefer-reflect": 0,
"prefer-spread": 0,
"prefer-template": 0,
"prefer-rest-params": 0,
"require-yield": 0,
"rest-spread-spacing": 0,
"sort-imports": 0,
"template-curly-spacing": 1,
"yield-star-spacing": 2
}
目前我在使用的规则是下面这个,兼容了之前的旧代码并且放弃了一部分样式规则。
{
"env": {
"node": true,
"es6": true
},
"parser": "babel-eslint",
"extends": ["eslint:recommended", "plugin:react/recommended"],
"parserOptions": {
"ecmaFeatures": {
"experimentalObjectRestSpread": true,
"jsx": true
},
"sourceType": "module"
},
"plugins": ["react"],
"globals": {
"fetch": false,
"__DEV__": false,
"WebSocket":false,
"FormData":false
},
"rules": {
"indent": ["error", 4],
"linebreak-style": ["error", "unix"],
"no-extra-semi": ["error"],
"no-unused-vars": 0,
"react/display-name": 0,
"react/prop-types":0,
"react/no-string-refs":0,
"keyword-spacing": "error",
"no-spaced-func": "error",
"space-in-parens": "error",
"no-console": ["error", {
"allow": ["log"]
}],
"curly": [2, "multi-line"],
"array-bracket-spacing": 2,
"block-spacing": 2,
"brace-style": 2,
"comma-spacing": 2,
"space-infix-ops": 2,
"arrow-spacing": 2,
"constructor-super": 2,
"no-var": 2,
"no-extra-parens":"error"
}
}
IDE 支持
WebStorm:Preferences → Languages & Frameworks → JavaScript → Code Quality Tools → Eslint → Enable (勾选) → Apply → OK
Atom:安装 linter-eslint
Sublime:安装 SublimeLinter
安装 SublimeLinter-contrib-eslint
IDE 配置统一规则
在根目录下创建一个样式规则文件 . editorconfig,这个文件就是为了统一不同的 IDE 下的规则的。这里简单设置了一下文件的编码格式 UTF8,以及最重要的统一使用 4 个空格!!
root = true
[*.{js}]
charset = utf-8
[*.js]
indent_style = space
indent_size = 4
如果不想让 ESlint 去检查 Jest 规范的文件,可以在根目录下创建 . eslintignore 文件,这个文件和 Git 的排除是一样的,模仿使用即可。
__tests__
.git
.vscode
android
bundle
ios
lib
node_modules
这里再教大家一个简单的全局样式处理方法,该方法就是使用 ESlint 的规则直接修改文件内容,执行命令node_modules/eslint/bin/eslint.js . --fix
就可以了,这里使用本地路径中的 ESlint。