Подключение ESLint
Пакет ESLint обязывает разработчиков придерживатся
одно стиля написания кода. Так, например, с его помощью можно запретить
определение неиспользуемых в коде переменных, или отменить использование
console.log(). При этом, во время компиляции в консоль будут выводится
соответствующие предупреждения, или ошибки.
Подключение ESLint в webpack
Для того, чтобы подключить ESLint в webpack, нужно установить несколько
пакетов и внести изменения в файл настроек webpack. Пакеты следующие:
- eslint — сам ESLint;
- babel-eslint — чтобы ESLint понимал ES6;
- eslint-plugin-react — нужен для того, чтобы ESLint знал что такое React.js
- eslint-loader — нужен для webpack;
Итак, установка пакетов выполняется командой:
$ npm install --save-dev eslint babel-eslint eslint-plugin-react esling-loader
Теперь, как пакеты установлены нужно настроить ESLint, то есть указать ему правила
за которыми он должен следить. Делается это с помощью файла настроек .eslintrc который
нужно разместить в корне проекта. Более подробно обо всех правилах вы можете почитать
на офф сайте, в разделе документации я же, представлю уже готовый файл настроек:
{
"parser": "babel-eslint",
"env": {
"browser": true,
"node": true,
"es6": true
},
"ecmaFeatures": {
"jsx": true,
"modules": true,
"classes": true
},
"plugins":[
"react"
],
"globals": {
"module": 0
},
"rules": {
// React
"react/display-name": 0,
"react/jsx-boolean-value": 1,
"react/jsx-closing-bracket-location": 1,
"react/jsx-curly-spacing": 1,
"react/jsx-max-props-per-line": 0,
"react/jsx-indent-props": 0,
"react/jsx-no-duplicate-props": 1,
"react/jsx-no-undef": 1,
"react/jsx-sort-prop-types": 0,
"react/jsx-sort-props": 0,
"react/jsx-uses-react": 1,
"react/jsx-uses-vars": 1, //Prevent variables used in JSX to be incorrectly marked as unused
"react/no-danger": 0,
"react/no-set-state": 1,
"react/no-did-mount-set-state": 1,
"react/no-did-update-set-state": 1,
"react/no-multi-comp": 1,
"react/no-unknown-property": 1,
"react/prop-types": 1,
"react/react-in-jsx-scope": 1,
"react/require-extension": 1,
"react/self-closing-comp": 1,
"react/sort-comp": 1,
"react/wrap-multilines": 1,
"no-cond-assign": 1, // disallow assignment in conditional expressions
"no-console": 0, // disallow use of console (off by default in the node environment)
"no-constant-condition": 1, // disallow use of constant expressions in conditions
"no-comma-dangle": 0, // disallow trailing commas in object literals
"no-control-regex": 1, // disallow control characters in regular expressions
"no-debugger": 1, // disallow use of debugger
"no-dupe-keys": 1, // disallow duplicate keys when creating object literals
"no-empty": 0, // disallow empty statements
"no-empty-character-class": 1, // disallow the use of empty character classes in regular expressions
"no-ex-assign": 1, // disallow assigning to the exception in a catch block
"no-extra-boolean-cast": 1, // disallow double-negation boolean casts in a boolean context
"no-extra-parens": 0, // disallow unnecessary parentheses (off by default)
"no-extra-semi": 1, // disallow unnecessary semicolons
"no-func-assign": 1, // disallow overwriting functions written as function declarations
"no-inner-declarations": 0, // disallow function or variable declarations in nested blocks
"no-invalid-regexp": 1, // disallow invalid regular expression strings in the RegExp constructor
"no-negated-in-lhs": 1, // disallow negation of the left operand of an in expression
"no-obj-calls": 1, // disallow the use of object properties of the global object (Math and JSON) as functions
"no-regex-spaces": 1, // disallow multiple spaces in a regular expression literal
"no-reserved-keys": 0, // disallow reserved words being used as object literal keys (off by default)
"no-sparse-arrays": 1, // disallow sparse arrays
"no-unreachable": 1, // disallow unreachable statements after a return, throw, continue, or break statement
"use-isnan": 1, // disallow comparisons with the value NaN
"valid-jsdoc": 0, // Ensure JSDoc comments are valid (off by default)
"valid-typeof": 1, // Ensure that the results of typeof are compared against a valid string
// Best Practices
// These are rules designed to prevent you from making mistakes. They either prescribe a better way of doing something or help you avoid footguns.
"block-scoped-var": 0, // treat var statements as if they were block scoped (off by default)
"complexity": 0, // specify the maximum cyclomatic complexity allowed in a program (off by default)
"consistent-return": 0, // require return statements to either always or never specify values
"curly": 1, // specify curly brace conventions for all control statements
"default-case": 0, // require default case in switch statements (off by default)
"dot-notation": 1, // encourages use of dot notation whenever possible
"eqeqeq": 1, // require the use of === and !==
"guard-for-in": 0, // make sure for-in loops have an if statement (off by default)
"no-alert": 1, // disallow the use of alert, confirm, and prompt
"no-caller": 1, // disallow use of arguments.caller or arguments.callee
"no-div-regex": 1, // disallow division operators explicitly at beginning of regular expression (off by default)
"no-else-return": 0, // disallow else after a return in an if (off by default)
"no-labels": 1, // disallow use of labels for anything other then loops and switches
"no-eq-null": 0, // disallow comparisons to null without a type-checking operator (off by default)
"no-eval": 1, // disallow use of eval()
"no-extend-native": 1, // disallow adding to native types
"no-extra-bind": 1, // disallow unnecessary function binding
"no-fallthrough": 1, // disallow fallthrough of case statements
"no-floating-decimal": 1, // disallow the use of leading or trailing decimal points in numeric literals (off by default)
"no-implied-eval": 1, // disallow use of eval()-like methods
"no-iterator": 1, // disallow usage of __iterator__ property
"no-lone-blocks": 1, // disallow unnecessary nested blocks
"no-loop-func": 0, // disallow creation of functions within loops
"no-multi-str": 0, // disallow use of multiline strings
"no-native-reassign": 0, // disallow reassignments of native objects
"no-new": 1, // disallow use of new operator when not part of the assignment or comparison
"no-new-func": 1, // disallow use of new operator for Function object
"no-new-wrappers": 1, // disallows creating new instances of String,Number, and Boolean
"no-octal": 1, // disallow use of octal literals
"no-octal-escape": 1, // disallow use of octal escape sequences in string literals, such as var foo = "Copyright \251";
"no-proto": 1, // disallow usage of __proto__ property
"no-redeclare": 0, // disallow declaring the same variable more then once
"no-return-assign": 1, // disallow use of assignment in return statement
"no-script-url": 1, // disallow use of javascript: urls.
"no-self-compare": 1, // disallow comparisons where both sides are exactly the same (off by default)
"no-sequences": 1, // disallow use of comma operator
"no-unused-expressions": 0, // disallow usage of expressions in statement position
"no-void": 1, // disallow use of void operator (off by default)
"no-warning-comments": 0, // disallow usage of configurable warning terms in comments": 1, // e.g. TODO or FIXME (off by default)
"no-with": 1, // disallow use of the with statement
"radix": 1, // require use of the second argument for parseInt() (off by default)
"vars-on-top": 0, // requires to declare all vars on top of their containing scope (off by default)
"wrap-iife": 0, // require immediate function invocation to be wrapped in parentheses (off by default)
"yoda": 1, // require or disallow Yoda conditions
// Strict Mode
// These rules relate to using strict mode.
"strict": 0, // require that all functions are run in strict mode
// Variables
// These rules have to do with variable declarations.
"no-catch-shadow": 1, // disallow the catch clause parameter name being the same as a variable in the outer scope (off by default in the node environment)
"no-delete-var": 1, // disallow deletion of variables
"no-label-var": 1, // disallow labels that share a name with a variable
"no-shadow": 1, // disallow declaration of variables already declared in the outer scope
"no-shadow-restricted-names": 1, // disallow shadowing of names such as arguments
"no-undef": 2, // disallow use of undeclared variables unless mentioned in a /*global */ block
"no-undefined": 0, // disallow use of undefined variable (off by default)
"no-undef-init": 1, // disallow use of undefined when initializing variables
"no-unused-vars": [1, {"vars": "all", "args": "none"}], // disallow declaration of variables that are not used in the code
"no-use-before-define": 0, // disallow use of variables before they are defined
// Node.js
// These rules are specific to JavaScript running on Node.js.
"handle-callback-err": 1, // enforces error handling in callbacks (off by default) (on by default in the node environment)
"no-mixed-requires": 1, // disallow mixing regular variable and require declarations (off by default) (on by default in the node environment)
"no-new-require": 1, // disallow use of new operator with the require function (off by default) (on by default in the node environment)
"no-path-concat": 1, // disallow string concatenation with __dirname and __filename (off by default) (on by default in the node environment)
"no-process-exit": 0, // disallow process.exit() (on by default in the node environment)
"no-restricted-modules": 1, // restrict usage of specified node modules (off by default)
"no-sync": 0, // disallow use of synchronous methods (off by default)
// Stylistic Issues
// These rules are purely matters of style and are quite subjective.
"key-spacing": 0,
"comma-spacing": 0,
"no-multi-spaces": 0,
"brace-style": 0, // enforce one true brace style (off by default)
"camelcase": 1, // require camel case names
"consistent-this": [1, "self"], // enforces consistent naming when capturing the current execution context (off by default)
"eol-last": 1, // enforce newline at the end of file, with no multiple empty lines
"func-names": 0, // require function expressions to have a name (off by default)
"func-style": 0, // enforces use of function declarations or expressions (off by default)
"new-cap": 0, // require a capital letter for constructors
"new-parens": 1, // disallow the omission of parentheses when invoking a constructor with no arguments
"no-nested-ternary": 0, // disallow nested ternary expressions (off by default)
"no-array-constructor": 1, // disallow use of the Array constructor
"no-lonely-if": 0, // disallow if as the only statement in an else block (off by default)
"no-new-object": 1, // disallow use of the Object constructor
"no-spaced-func": 1, // disallow space between function identifier and application
"semi-spacing": 1, // disallow space before semicolon
"no-ternary": 0, // disallow the use of ternary operators (off by default)
"no-trailing-spaces": 1, // disallow trailing whitespace at the end of lines
"no-underscore-dangle": 0, // disallow dangling underscores in identifiers
"no-mixed-spaces-and-tabs": 1, // disallow mixed spaces and tabs for indentation
"quotes": [1, "single"], // specify whether double or single quotes should be used
"quote-props": 0, // require quotes around object literal property names (off by default)
"semi": 1, // require or disallow use of semicolons instead of ASI
"sort-vars": 0, // sort variables within the same declaration block (off by default)
"keyword-spacing": 1, // require a space after certain keywords (off by default)
"space-in-brackets": 0, // require or disallow spaces inside brackets (off by default)
"space-in-parens": 0, // require or disallow spaces inside parentheses (off by default)
"space-infix-ops": 1, // require spaces around operators
"max-nested-callbacks": 0, // specify the maximum depth callbacks can be nested (off by default)
"one-var": 0, // allow just one var statement per function (off by default)
"wrap-regex": 0, // require regex literals to be wrapped in parentheses (off by default)
// Legacy
// The following rules are included for compatibility with JSHint and JSLint. While the names of the rules may not match up with the JSHint/JSLint counterpart, the functionality is the same.
"max-depth": 0, // specify the maximum depth that blocks can be nested (off by default)
"max-len": 0, // specify the maximum length of a line in your program (off by default)
"max-params": 0, // limits the number of parameters that can be used in the function declaration. (off by default)
"max-statements": 0, // specify the maximum number of statement allowed in a function (off by default)
"no-bitwise": 1, // disallow use of bitwise operators (off by default)
"no-plusplus": 0 // disallow use of unary operators, ++ and -- (off by default)
}
}
Подключение ESLint в Sublime Text 3
Лично я пользуюсь Sublime Text 3 и хотел бы, чтобы по возможности, он в интерактивном режиме, во время написания кода, подсвечивал мне ошибки. Такая возможность есть и для этой цели существует плагин для Sublime Text 3 — SublimeLinter. Для коректной работы этого плагина, перечисленные выше пакеты должны быть установлены глобально, кроме пакета eslint-loader.
Для того чтобы просмотреть список установленных глобально пакетов, можно воспользоватся командой:
$ npm -g ls --depth=0
Команда для конкретного проекта аналогичная, нужно только убрать ключ -g.
Итак, устанавливаем пакеты глобально:
$ npm install -g eslint babel-esling eslint-plugin-react
Теперь, устанавливаем два плагина:
- SublimeLinter
- SublimeLinter-contrib-eslint
Этого достаточно для подключения ESLint в Sublime Text 3. Файл настроек .eslintrc, само сабой разумеется, должен быть в корне проекта.