node-jscs

JSCS — JavaScript Code Style.

jscs is a code style checker. You can configure jscs for your project in detail using over 60 validation rules, including presets from popular style guides like jQuery.

This is a documentation for the development version, please refer to the https://www.npmjs.org/package/jscs instead

Presets

• Crockford - http://javascript.crockford.com/code.html
• Google - https://google-styleguide.googlecode.com/svn/trunk/javascriptguide.xml
• jQuery - https://contribute.jquery.org/style-guide/js/
• MDCS - https://github.com/mrdoob/three.js/wiki/Mr.doob's-Code-Style%E2%84%A2
• Wikimedia - https://www.mediawiki.org/wiki/Manual:Coding_conventions/JavaScript
• Yandex - https://github.com/ymaps/codestyle/blob/master/js.md

Friendly packages

• Grunt task: https://github.com/gustavohenke/grunt-jscs/
• Gulp task: https://github.com/sindresorhus/gulp-jscs/
• SublimeText 3 Plugin: https://github.com/SublimeLinter/SublimeLinter-jscs/
• Syntastic VIM Plugin: https://github.com/scrooloose/syntastic/.../syntax_checkers/javascript/jscs.vim/
• Web Essentials for Visual Studio 2013: https://github.com/madskristensen/WebEssentials2013/

Extensions

• Brackets Extension: https://github.com/globexdesigns/brackets-jscs
• A team city reporter: https://github.com/wurmr/jscs-teamcity-reporter
• JSdoc rules extension: https://github.com/zxqfox/jscs-jsdoc

Installation

jscs can be installed using npm:

npm install jscs -g

To run jscs, you can use the following command from the project root:

jscs path[ path[...]]

You can also pipe input into jscs:

cat myfile.js | jscs

CLI

--config

Allows to define path to the config file.

jscs path[ path[...]] --config=./.config.json

If there is no --config option specified, jscs it will consequentially search for jscsConfig option in package.json file then for .jscsrc and .jscs.json files in the current working directory then in nearest ancestor until it hits the system root.

--preset

If defined will use predefined rules for specific code style.

jscs path[ path[...]] --preset=jquery

--reporter

jscs itself provides six reporters: checkstyle, console, inline, junit and text.

jscs path[ path[...]] --reporter=console

But you also can specify your own reporter, since this flag accepts relative or absolute paths too.

jscs path[ path[...]] --reporter=./some-dir/my-reporter.js

--no-colors

Will be removed. Clean output without colors.

--help

Outputs usage information.

--verbose

Prepends the name of the offending rule to all error messages.

--version

Outputs version of jscs.

Options

additionalRules

Path to load additional rules

Type: Array

Values: Array of file matching patterns

Example

"additionalRules": ["project-rules/*.js"]

preset

Extends defined rules with preset rules.

Type: String

Values: "crockford", "google", "jquery", "mdcs", "wikimedia", "yandex"

Example

"preset": "jquery"

If you want specifically disable preset rule assign it to null, like so:

{
    "preset": "jquery",
    "requireCurlyBraces": null
}

excludeFiles

Disables style checking for specified paths.

Type: Array

Values: Array of file matching patterns

Example

"excludeFiles": ["node_modules/**"]

fileExtensions

Changes the set of file extensions that will be processed.

Type: Array or String or "*"

Values: A single file extension or an Array of file extensions, beginning with a .. The matching is case insensitive. If "*" is provided, all files regardless of extension will match.

Example

"fileExtensions": [".js", ".jsx"]

Default

"fileExtensions": [".js"]

Error Suppression

Disabling Rules From Presets

After using the preset option, you can set any rules values to null to remove it. i.e. The following config will use the jQuery preset except will not require the use of a.b over a['b'].:

{
    "preset": "jquery",
    "requireDotNotation": null
}

Inline Comments

You can disable and reenable rules inline with two special comments: //jscs:disable and //jscs:enable. Spacing in these comments is fairly lenient. All of the following are equivalent:

/* jscs: enable */
// jscs: enable
//jscs: enable
// jscs:enable

You can use them to disable rules in several ways.

Disabling All Rules

Simply using //jscs:disable or //jscs:enable will disable all rules.

var a = b;
//jscs:disable
var c = d; // all errors on this line will be ignored
//jscs:enable
var e = f; // all errors on this line will be reported

Disabling Specific Rules

Including a comma separated list of rules to modify after //jscs:disable or //jscs:enable will modify only those rules.

//jscs:disable requireCurlyBraces
if (x) y(); // all errors from requireCurlyBraces on this line will be ignored
//jscs:enable requireCurlyBraces
if (z) a(); // all errors, including from requireCurlyBraces, on this line will be reported

You can enable all rules after disabling a specific rule, and that rule becomes reenabled as well.

//jscs:disable requireCurlyBraces
if (x) y(); // all errors from requireCurlyBraces on this line will be ignored
//jscs:enable
if (z) a(); // all errors, even from requireCurlyBraces, will be reported

You can disable multiple rules at once and progressively reeanble them.

//jscs:disable requireCurlyBraces, requireDotNotation
if (x['a']) y(); // all errors from requireCurlyBraces OR requireDotNotation on this line will be ignored
//jscs:enable requireCurlyBraces
if (z['a']) a(); // all errors from requireDotNotation, but not requireCurlyBraces, will be ignored
//jscs:enable requireDotNotation
if (z['a']) a(); // all errors will be reported

Rules

requireCurlyBraces

Requires curly braces after statements.

Type: Array

Values: Array of quoted keywords

JSHint: curly

Example

"requireCurlyBraces": [
    "if",
    "else",
    "for",
    "while",
    "do",
    "try",
    "catch",
    "case",
    "default"
]

Valid

if (x) {
    x++;
}

Invalid

if (x) x++;

requireSpaceAfterKeywords

Requires space after keyword.

Type: Array

Values: Array of quoted keywords

Example

"requireSpaceAfterKeywords": [
    "if",
    "else",
    "for",
    "while",
    "do",
    "switch",
    "return",
    "try",
    "catch"
]

Valid

return true;

Invalid

if(x) {
    x++;
}

disallowSpaceAfterKeywords

Disallows space after keyword.

Type: Array

Values: Array of quoted keywords

Example

"disallowSpaceAfterKeywords": [
    "if",
    "else",
    "for",
    "while",
    "do",
    "switch",
    "try",
    "catch"
]

Valid

if(x > y) {
    y++;
}

requireSpaceBeforeBlockStatements

Requires space before block statements (for loops, control structures).

Type: Boolean

Values: true

Example

"requireSpaceBeforeBlockStatements": true

Valid

if (cond) {
  foo();
}

for (var e in elements) {
  bar(e);
}

while (cond) {
  foo();
}

Invalid

if (cond){
  foo();
}

for (var e in elements){
  bar(e);
}

while (cond){
  foo();
}

disallowSpaceBeforeBlockStatements

Disallows space before block statements (for loops, control structures).

Type: Boolean

Values: true

Example

"disallowSpaceBeforeBlockStatements": true

Valid

if (cond){
  foo();
}

for (var e in elements){
  bar(e);
}

while (cond){
  foo();
}

Invalid

if (cond) {
  foo();
}

for (var e in elements) {
  bar(e);
}

while (cond) {
  foo();
}

requireParenthesesAroundIIFE

Requires parentheses around immediately invoked function expressions.

Type: Boolean

Values: true

JSHint: immed

Example

"requireParenthesesAroundIIFE": true

Valid

var a = (function(){ return 1; })();
var b = (function(){ return 2; }());
var c = (function(){ return 3; }).call(this, arg1);
var d = (function(){ return 3; }.call(this, arg1));
var e = (function(){ return d; }).apply(this, args);
var f = (function(){ return d; }.apply(this, args));

Invalid

var a = function(){ return 1; }();
var c = function(){ return 3; }.call(this, arg1);
var d = function(){ return d; }.apply(this, args);

requireSpacesInConditionalExpression

Requires space before and/or after ? or : in conditional expressions.

Type: Object or Boolean

Values: "afterTest", "beforeConsequent", "afterConsequent", "beforeAlternate" as child properties, or true to set all properties to true. Child properties must be set to true.

Example

"requireSpacesInConditionalExpression": {
    "afterTest": true,
    "beforeConsequent": true,
    "afterConsequent": true,
    "beforeAlternate": true
}

Valid

var a = b ? c : d;
var a= b ? c : d;

Invalid

var a = b? c : d;
var a = b ?c : d;
var a = b ? c: d;
var a = b ? c :d;

disallowSpacesInConditionalExpression

Disallows space before and/or after ? or : in conditional expressions.

Type: Object or Boolean

Values: "afterTest", "beforeConsequent", "afterConsequent", "beforeAlternate" as child properties, or true to set all properties to true. Child properties must be set to true.

Example

"disallowSpacesInConditionalExpression": {
    "afterTest": true,
    "beforeConsequent": true,
    "afterConsequent": true,
    "beforeAlternate": true
}

Valid

var a = b?c:d;
var a= b?c:d;

Invalid

var a = b ?c:d;
var a = b? c:d;
var a = b?c :d;
var a = b?c: d;

requireSpacesInFunctionExpression

Requires space before () or {} in function expressions (both named and anonymous).

Type: Object

Values: "beforeOpeningRoundBrace" and "beforeOpeningCurlyBrace" as child properties. Child properties must be set to true.

Example

"requireSpacesInFunctionExpression": {
    "beforeOpeningRoundBrace": true,
    "beforeOpeningCurlyBrace": true
}

Valid

function () {}
function a () {}

Invalid

function() {}
function (){}

disallowSpacesInFunctionExpression

Disallows space before () or {} in function expressions (both named and anonymous).

Type: Object

Values: "beforeOpeningRoundBrace" and "beforeOpeningCurlyBrace" as child properties. Child properties must be set to true.

Example

"disallowSpacesInFunctionExpression": {
    "beforeOpeningRoundBrace": true,
    "beforeOpeningCurlyBrace": true
}

Valid

function(){}
function a(){}

Invalid

function () {}
function a (){}

requireSpacesInAnonymousFunctionExpression

Requires space before () or {} in anonymous function expressions.

Type: Object

Values: "beforeOpeningRoundBrace" and "beforeOpeningCurlyBrace" as child properties. Child properties must be set to true.

Example

"requireSpacesInAnonymousFunctionExpression": {
    "beforeOpeningRoundBrace": true,
    "beforeOpeningCurlyBrace": true
}

Valid

function () {}

Invalid

function() {}
function (){}

disallowSpacesInAnonymousFunctionExpression

Disallows space before () or {} in anonymous function expressions.

Type: Object

Values: "beforeOpeningRoundBrace" and "beforeOpeningCurlyBrace" as child properties. Child properties must be set to true.

Example

"disallowSpacesInAnonymousFunctionExpression": {
    "beforeOpeningRoundBrace": true,
    "beforeOpeningCurlyBrace": true
}

Valid

function(){}

Invalid

function () {}
function (){}

requireSpacesInNamedFunctionExpression

Requires space before () or {} in named function expressions.

Type: Object

Values: "beforeOpeningRoundBrace" and "beforeOpeningCurlyBrace" as child properties. Child properties must be set to true.

Example

"requireSpacesInNamedFunctionExpression": {
    "beforeOpeningRoundBrace": true,
    "beforeOpeningCurlyBrace": true
}

Valid

function a () {}

Invalid

function a() {}
function a(){}

disallowSpacesInNamedFunctionExpression

Disallows space before () or {} in named function expressions.

Type: Object

Values: "beforeOpeningRoundBrace" and "beforeOpeningCurlyBrace" as child properties. Child properties must be set to true.

Example

"disallowSpacesInNamedFunctionExpression": {
    "beforeOpeningRoundBrace": true,
    "beforeOpeningCurlyBrace": true
}

Valid

function a(){}

Invalid

function a () {}
function a (){}

requireSpacesInFunctionDeclaration

Requires space before () or {} in function declarations.

Type: Object

Values: "beforeOpeningRoundBrace" and "beforeOpeningCurlyBrace" as child properties. Child properties must be set to true.

Example

"requireSpacesInFunctionDeclaration": {
    "beforeOpeningRoundBrace": true,
    "beforeOpeningCurlyBrace": true
}

Valid

function a () {}

Invalid

function a() {}
function a (){}

disallowSpacesInFunctionDeclaration

Disallows space before () or {} in function declarations.

Type: Object

Values: "beforeOpeningRoundBrace" and "beforeOpeningCurlyBrace" as child properties. Child properties must be set to true.

Example

"disallowSpacesInFunctionDeclaration": {
    "beforeOpeningRoundBrace": true,
    "beforeOpeningCurlyBrace": true
}

Valid

function a(){}

Invalid

function a () {}
function a (){}

requireSpacesInFunction

Requires space before () or {} in function declarations and expressions.

Type: Object

Values: "beforeOpeningRoundBrace" and "beforeOpeningCurlyBrace" as child properties. Child properties must be set to true.

Example

"requireSpacesInFunction": {
    "beforeOpeningRoundBrace": true,
    "beforeOpeningCurlyBrace": true
}

Valid

function a () {}

Invalid

function a() {}
function a (){}

disallowSpacesInFunction

Disallows space before () or {} in function declarations and expressions.

Type: Object

Values: "beforeOpeningRoundBrace" and "beforeOpeningCurlyBrace" as child properties. Child properties must be set to true.

Example

"disallowSpacesInFunction": {
    "beforeOpeningRoundBrace": true,
    "beforeOpeningCurlyBrace": true
}

Valid

function a(){}

Invalid

function a () {}
function a (){}

disallowMultipleVarDecl

Disallows multiple var declaration (except for-loop).

Type: Boolean

Values: true

Example

"disallowMultipleVarDecl": true

Valid

var x = 1;
var y = 2;

for (var i = 0, j = arr.length; i < j; i++) {}

Invalid

var x = 1,
    y = 2;

requireMultipleVarDecl

Requires multiple var declaration.

Type: Boolean or String

Values: true or "onevar"

if requireMultipleVarDecl defined as a true value, it will report only consecutive vars, if, on the other hand, value equals to "onevar" string, requireMultipleVarDecl will allow only one var per function scope.

JSHint: onevar

Example

"requireMultipleVarDecl": true

Valid

var x = 1,
    y = 2;

Invalid

var x = 1;
var y = 2;

requireBlocksOnNewline

Requires blocks to begin and end with a newline

Type: Boolean or Integer

Values: true validates all non-empty blocks, Integer specifies a minimum number of statements in the block before validating.

Example

"requireBlocksOnNewline": true

Valid for mode true

if (true) {
    doSomething();
}
var abc = function() {};

Invalid

if (true) {doSomething();}

Valid for mode 1

if (true) {
    doSomething();
    doSomethingElse();
}
if (true) { doSomething(); }
var abc = function() {};

Invalid

if (true) { doSomething(); doSomethingElse(); }

requirePaddingNewlinesInBlocks

Requires blocks to begin and end with 2 newlines

Type: Boolean or Integer

Values: true validates all non-empty blocks, Integer specifies a minimum number of statements in the block before validating.

Example

"requirePaddingNewlinesInBlocks": true

Valid for mode true

if (true) {

    doSomething();

}
var abc = function() {};

Invalid

if (true) {doSomething();}
if (true) {
    doSomething();
}

Valid for mode 1

if (true) {

    doSomething();
    doSomethingElse();

}
if (true) {
    doSomething();
}
if (true) { doSomething(); }
var abc = function() {};

Invalid

if (true) { doSomething(); doSomethingElse(); }
if (true) {
    doSomething();
    doSomethingElse();
}

disallowPaddingNewlinesInBlocks

Disallows blocks from beginning and ending with 2 newlines.

Type: Boolean

Values: true validates all non-empty blocks.

Example

"disallowPaddingNewlinesInBlocks": true

Valid

if (true) {
    doSomething();
}
if (true) {doSomething();}
var abc = function() {};

Invalid

if (true) {

    doSomething();

}

disallowEmptyBlocks

Disallows empty blocks (except for catch blocks).

Type: Boolean

Values: true

JSHint: noempty

Example

"disallowEmptyBlocks": true

Valid

if ( a == b ) { c = d; }
try { a = b; } catch( e ){}

Invalid

if ( a == b ) { } else { c = d; }

disallowSpacesInsideObjectBrackets

Disallows space after opening object curly brace and before closing.

Type: Boolean or String

Values: "all" or true for strict mode, "nested" ignores closing brackets in a row.

Example

"disallowSpacesInsideObjectBrackets": "all"

Valid for mode "all"

var x = {a: {b: 1}};

Valid for mode "nested"

var x = { a: {b: 1} };

Invalid

var x = { a: { b: 1 } };

disallowSpacesInsideArrayBrackets

Disallows space after opening array square bracket and before closing.

Type: Boolean or String

Values: "all" or true for strict mode, "nested" ignores closing brackets in a row.

Example

"disallowSpacesInsideArrayBrackets": "all"

Valid for mode "all"

var x = [[1]];

Valid for mode "nested"

var x = [ [1] ];

Invalid

var x = [ [ 1 ] ];

disallowSpacesInsideParentheses

Disallows space after opening round bracket and before closing.

Type: Boolean

Values: true

Example

"disallowSpacesInsideParentheses": true

Valid

var x = (1 + 2) * 3;

Invalid

var x = ( 1 + 2 ) * 3;

requireSpacesInsideObjectBrackets

Requires space after opening object curly brace and before closing.

Type: String

Values: "all" for strict mode, "allButNested" ignores closing brackets in a row.

Example

"requireSpacesInsideObjectBrackets": "all"

Valid for mode "all"

var x = { a: { b: 1 } };

Valid for mode "allButNested"

var x = { a: { b: 1 }};

Invalid

var x = {a: 1};

requireSpacesInsideArrayBrackets

Requires space after opening array square bracket and before closing.

Type: String

Values: "all" for strict mode, "allButNested" ignores closing brackets in a row.

Example

"requireSpacesInsideArrayBrackets": "all"

Valid for mode "all"

var x = [ 1 ];

Valid for mode "allButNested"

var x = [[ 1 ], [ 2 ]];

Invalid

var x = [1];

requireSpacesInsideParentheses

Requires space after opening round bracket and before closing.

Type: String

Values: "all" for strict mode, "allButNested" ignores nested brackets in a row.

Example

"requireSpacesInsideParentheses": "all"

Valid for mode "all"

var x = Math.pow( ( 1 + 2 ), ( 3 + 4 ) );

Valid for mode "allButNested"

var x = Math.pow(( 1 + 2 ), ( 3 + 4 ));

Invalid

var x = Math.pow(1 + 2, 3 + 4);

disallowQuotedKeysInObjects

Disallows quoted keys in object if possible.

Type: String or Boolean

Values:

• true for strict mode
• "allButReserved" allows ES3+ reserved words to remain quoted which is helpful when using this option with JSHint's es3 flag.

Example

"disallowQuotedKeysInObjects": true

Valid for mode true

var x = { a: { default: 1 } };

Valid for mode "allButReserved"

var x = {a: 1, 'default': 2};

Invalid

var x = {'a': 1};

disallowDanglingUnderscores

Disallows identifiers that start or end in _, except for some popular exceptions:

• _ (underscore.js)
• __filename (node.js global)
• __dirname (node.js global)

Type: Boolean

Values: true

JSHint: nomen

Example

"disallowDanglingUnderscores": true

Valid

var x = 1;
var y = _.extend;
var z = __dirname;
var w = __filename;
var x_y = 1;

Invalid

var _x = 1;
var x_ = 1;
var x_y_ = 1;

disallowSpaceAfterObjectKeys

Disallows space after object keys.

Type: Boolean

Values: true

Example

"disallowSpaceAfterObjectKeys": true

Valid

var x = {a: 1};

Invalid

var x = {a : 1};

requireSpaceAfterObjectKeys

Requires space after object keys.

Type: Boolean

Values: true

Example

"requireSpaceAfterObjectKeys": true

Valid

var x = {a : 1};

Invalid

var x = {a: 1};

disallowCommaBeforeLineBreak

Disallows commas as last token on a line in lists.

Type: Boolean

Values: true

JSHint: laxcomma

Example

"disallowCommaBeforeLineBreak": true

Valid

var x = {
    one: 1
    , two: 2
};
var y = { three: 3, four: 4};

Invalid

var x = {
    one: 1,
    two: 2
};

requireCommaBeforeLineBreak

Requires commas as last token on a line in lists.

Type: Boolean

Values: true

JSHint: laxcomma

Example

"requireCommaBeforeLineBreak": true

Valid

var x = {
    one: 1,
    two: 2
};
var y = { three: 3, four: 4};

Invalid

var x = {
    one: 1
    , two: 2
};

requireAlignedObjectValues

Requires proper alignment in object literals.

Type: String

Values:

• "all" for strict mode,
• "ignoreFunction" ignores objects if one of the property values is a function expression,
• "ignoreLineBreak" ignores objects if there are line breaks between properties

Example

"requireAlignedObjectValues": "all"

Valid

var x = {
    a   : 1,
    bcd : 2,
    ef  : 'str'
};

Invalid

var x = {
    a : 1,
    bcd : 2,
    ef : 'str'
};

requireOperatorBeforeLineBreak

Requires operators to appear before line breaks and not after.

Type: Array or Boolean

Values: Array of quoted operators or true to require all possible binary operators to appear before line breaks

JSHint: laxbreak

Example

"requireOperatorBeforeLineBreak": [
    "?",
    "=",
    "+",
    "-",
    "/",
    "*",
    "==",
    "===",
    "!=",
    "!==",
    ">",
    ">=",
    "<",
    "<="
]

Valid

x = y ? 1 : 2;
x = y ?
    1 : 2;

Invalid

x = y
    ? 1 : 2;

disallowSpaceAfterPrefixUnaryOperators

Requires sticking unary operators to the right.

Type: Array or Boolean

Values: Array of quoted operators or true to disallow space after prefix for all unary operators

Example

"disallowSpaceAfterPrefixUnaryOperators": ["++", "--", "+", "-", "~", "!"]

Valid

x = !y; y = ++z;

Invalid

x = ! y; y = ++ z;

requireSpaceAfterPrefixUnaryOperators

Disallows sticking unary operators to the right.

Type: Array or Boolean

Values: Array of quoted operators or true to require space after prefix for all unary operators

Example

"requireSpaceAfterPrefixUnaryOperators": ["++", "--", "+", "-", "~", "!"]

Valid

x = ! y; y = ++ z;

Invalid

x = !y; y = ++z;

disallowSpaceBeforePostfixUnaryOperators

Requires sticking unary operators to the left.

Type: Array or Boolean

Values: Array of quoted operators or true to disallow space before postfix for all unary operators (i.e. increment/decrement operators)

Example

"disallowSpaceBeforePostfixUnaryOperators": ["++", "--"]

Valid

x = y++; y = z--;

Invalid

x = y ++; y = z --;

requireSpaceBeforePostfixUnaryOperators

Disallows sticking unary operators to the left.

Type: Array or Boolean

Values: Array of quoted operators or true to require space before postfix for all unary operators (i.e. increment/decrement operators)

Example

"requireSpaceBeforePostfixUnaryOperators": ["++", "--"]

Valid

x = y ++; y = z --;

Invalid

x = y++; y = z--;

disallowSpaceBeforeBinaryOperators

Requires sticking binary operators to the left.

Type: Array or Boolean

Values: Array of quoted operators or true to disallow space before all possible binary operators

Example

"disallowSpaceBeforeBinaryOperators": [
    "=",
    ",",
    "+",
    "-",
    "/",
    "*",
    "==",
    "===",
    "!=",
    "!=="
    // etc
]

Valid

x+ y;

Invalid

x + y;

requireSpaceBeforeBinaryOperators

Disallows sticking binary operators to the left.

Type: Array or Boolean

Values: Array of quoted operators or true to require space before all possible binary operators without comma operator, since it's rarely used with this rule

Example

"requireSpaceBeforeBinaryOperators": [
    "=",
    ",",
    "+",
    "-",
    "/",
    "*",
    "==",
    "===",
    "!=",
    "!=="
    // etc
]

Valid

x !== y;

Invalid

x!== y;

disallowSpaceAfterBinaryOperators

Requires sticking binary operators to the right.

Type: Array or Boolean

Values: Array of quoted operators or true to disallow space after all possible binary operators

Example

"disallowSpaceAfterBinaryOperators": [
    "=",
    ",",
    "+",
    "-",
    "/",
    "*",
    "==",
    "===",
    "!=",
    "!=="
    // etc
]

Valid

x +y;

Invalid

x+ y;

requireSpaceAfterBinaryOperators

Disallows sticking binary operators to the right.

Type: Array or Boolean

Values: Array of quoted operators or true to require space after all possible binary operators

Example

"requireSpaceAfterBinaryOperators": [
    "=",
    ",",
    "+",
    "-",
    "/",
    "*",
    "==",
    "===",
    "!=",
    "!=="
    // etc
]

Valid

x + y;

Invalid

x +y;

disallowImplicitTypeConversion

Disallows implicit type conversion.

Type: Array

Values: Array of quoted types

Example

"disallowImplicitTypeConversion": ["numeric", "boolean", "binary", "string"]

Valid

x = Boolean(y);
x = Number(y);
x = String(y);
x = s.indexOf('.') !== -1;

Invalid

x = !!y;
x = +y;
x = '' + y;
x = ~s.indexOf('.');

requireCamelCaseOrUpperCaseIdentifiers

Requires identifiers to be camelCased or UPPERCASE_WITH_UNDERSCORES

Type: Boolean or String

Values: true or "ignoreProperties"

JSHint: camelcase

Example

"requireCamelCaseOrUpperCaseIdentifiers": true

Valid for mode true

var camelCase = 0;
var CamelCase = 1;
var _camelCase = 2;
var camelCase_ = 3;
var UPPER_CASE = 4;

Invalid for mode true

var lower_case = 1;
var Mixed_case = 2;
var mixed_Case = 3;

Valid for mode ignoreProperties

var camelCase = 0;
var CamelCase = 1;
var _camelCase = 2;
var camelCase_ = 3;
var UPPER_CASE = 4;
var obj.snake_case = 5;
var camelCase = { snake_case: 6 };

Invalid for mode ignoreProperties

var lower_case = 1;
var Mixed_case = 2;
var mixed_Case = 3;
var snake_case = { snake_case: 6 };

disallowKeywords

Disallows usage of specified keywords.

Type: Array

Values: Array of quoted keywords

Example

"disallowKeywords": ["with"]

Invalid

with (x) {
    prop++;
}

disallowMultipleLineStrings

Disallows strings that span multiple lines without using concatenation.

Type: Boolean

Values: true

JSHint: multistr

Example

"disallowMultipleLineStrings": true

Valid

var x = "multi" +
        "line";
var y = "single line";

Invalid

var x = "multi \
        line";

disallowMultipleLineBreaks

Disallows multiple blank lines in a row.

Type: Boolean

Values: true

Example

"disallowMultipleLineBreaks": true

Valid

var x = 1;

x++;

Invalid

var x = 1;


x++;

validateLineBreaks

Option to check line break characters

Type: String

Values: "CR", "LF", "CRLF"

Example

"validateLineBreaks": "LF"

Valid

var x = 1;<LF>
x++;

Invalid

var x = 1;<CRLF>
x++;

validateQuoteMarks

Requires all quote marks to be either the supplied value, or consistent if true

Type: String or Object

Values:

• "\"": all strings require double quotes
• "'": all strings require single quotes
• true: all strings require the quote mark first encountered in the source code
• Object:
  • escape: allow the "other" quote mark to be used, but only to avoid having to escape
  • mark: the same effect as the non-object values

JSHint: quotmark

Example

"validateQuoteMarks": "\""

"validateQuoteMarks": { "mark": "\"", "escape": true }

Valid example for mode { "mark": "\"", "escape": true }

var x = "x";
var y = '"x"';

Invalid example for mode { "mark": "\"", "escape": true }

var x = "x";
var y = 'x';

Valid example for mode "\"" or mode true

var x = "x";

Valid example for mode "'" or mode true

var x = 'x';

Invalid example for mode true

var x = "x", y = 'y';

validateIndentation

Validates indentation for arrays, objects, switch statements, and block statements

Type: Integer or String

Values: A positive integer or "\t"

JSHint: indent

Example

"validateIndentation": "\t"

Valid example for mode 2

if (a) {
  b=c;
  function(d) {
    e=f;
  }
}

Invalid example for mode 2

if (a) {
   b=c;
function(d) {
       e=f;
}
}

Valid example for mode "\t"

if (a) {
    b=c;
    function(d) {
        e=f;
    }
}

Invalid example for mode "\t"

if (a) {
     b=c;
function(d) {
           e=f;
 }
}

disallowMixedSpacesAndTabs

Requires lines to not contain both spaces and tabs consecutively, or spaces after tabs only for alignment if "smart"

Type: Boolean or String

Values: true or "smart"

JSHint: smarttabs

Example

"disallowMixedSpacesAndTabs": true

Valid example for mode true

\tvar foo = "blah blah";
\s\s\s\svar foo = "blah blah";
\t/**
\t\s*
\t\s*/ //a single space to align the star in a multi-line comment is allowed

Invalid example for mode true

\t\svar foo = "blah blah";
\s\tsvar foo = "blah blah";

Valid example for mode "smart"

\tvar foo = "blah blah";
\t\svar foo = "blah blah";
\s\s\s\svar foo = "blah blah";
\t/**
\t\s*
\t\s*/ //a single space to align the star in a multi-line comment is allowed

Invalid example for mode "smart"

\s\tsvar foo = "blah blah";

disallowTrailingWhitespace

Requires all lines to end on a non-whitespace character

Type: Boolean

Values: true

JSHint: trailing

Example

"disallowTrailingWhitespace": true

Valid

var foo = "blah blah";

Invalid

var foo = "blah blah"; //<-- whitespace character here

disallowTrailingComma

Disallows an extra comma following the final element of an array or object literal.

Type: Boolean

Values: true

JSHint: es3

Example

"disallowTrailingComma": true

Valid

var foo = [1, 2, 3];
var bar = {a: "a", b: "b"}

Invalid

var foo = [1, 2, 3, ];
var bar = {a: "a", b: "b", }

requireTrailingComma

Requires an extra comma following the final element of an array or object literal.

Type: Boolean or Object

Values:

• true: validates all arrays and objects
• Object:
  • ignoreSingleValue: allows single property objects and single element arrays to not require a trailing comma

Example

"requireTrailingComma": true

Valid

var foo = [1, 2, 3,];
var bar = {a: "a", b: "b",}

Valid with ignoreSingleValue

var car = [1];
var dar = {a: "a"};

Invalid

var foo = [1, 2, 3];
var bar = {a: "a", b: "b"}

disallowKeywordsOnNewLine

Disallows placing keywords on a new line.

Type: Array

Values: Array of quoted keywords

Example

"disallowKeywordsOnNewLine": ["else"]

Valid

if (x < 0) {
    x++;
} else {
    x--;
}

Invalid

if (x < 0) {
    x++;
}
else {
    x--;
}

requireKeywordsOnNewLine

Requires placing keywords on a new line.

Type: Array

Values: Array of quoted keywords

Example

"requireKeywordsOnNewLine": ["else"]

Valid

if (x < 0) {
    x++;
}
else {
    x--;
}

Invalid

if (x < 0) {
    x++;
} else {
    x--;
}

requireLineFeedAtFileEnd

Requires placing line feed at file end.

Type: Boolean

Values: true

Example

"requireLineFeedAtFileEnd": true

maximumLineLength

Requires all lines to be at most the number of characters specified

Type: Integer or Object

Values:

• Integer: lines should be at most the number of characters specified
• Object:
  • value: (required) lines should be at most the number of characters specified
  • tabSize: (default: 1) considered the tab character as number of specified spaces
  • allowComments: (default: false) allows comments to break the rule
  • allowUrlComments: (default: false) allows comments with long urls to break the rule
  • allowRegex: (default: false) allows regular expression literals to break the rule

JSHint: maxlen

Example

"maximumLineLength": 40

Valid

var aLineOf40Chars = 123456789012345678;

Invalid

var aLineOf41Chars = 1234567890123456789;

requireCapitalizedConstructors

Requires constructors to be capitalized (except for this)

Type: Boolean

Values: true

JSHint: newcap

Example

"requireCapitalizedConstructors": true

Valid

var a = new B();
var c = new this();

Invalid

var d = new e();

safeContextKeyword

Option to check var that = this expressions

Type: Array or String

Values: String value used for context local declaration

Example

"safeContextKeyword": ["that"]

Valid

var that = this;

Invalid

var _this = this;

requireDotNotation

Requires member expressions to use dot notation when possible

Type: Boolean

Values: true

JSHint: sub

Example

"requireDotNotation": true

Valid

var a = b[c];
var a = b.c;
var a = b[c.d];
var a = b[1];
var a = b['while']; //reserved word

Invalid

var a = b['c'];

requireYodaConditions

Requires the variable to be the right hand operator when doing a boolean comparison

Type: Boolean

Values: true

Example

"requireYodaConditions": true

Valid

if (1 == a) {
  return
}

Invalid

if (a == 1) {
  return
}

disallowYodaConditions

Requires the variable to be the left hand operator when doing a boolean comparison

Type: Boolean

Values: true

Example

"disallowYodaConditions": true

Valid

if (a == 1) {
  return
}

Invalid

if (1 == a) {
  return
}

validateJSDoc

Enables JSDoc validation.

Type: Object

Values:

• "checkParamNames" ensures param names in jsdoc and in function declaration are equal
• "requireParamTypes" ensures params in jsdoc contains type
• "checkRedundantParams" reports redundant params in jsdoc

Example

"validateJSDoc": {
    "checkParamNames": true,
    "checkRedundantParams": true,
    "requireParamTypes": true
}

Valid

/**
 * Adds style error to the list
 *
 * @param {String} message
 * @param {Number|Object} line
 * @param {Number} [column]
 */
add: function(message, line, column) {
}

Invalid

/**
 * Adds style error to the list
 *
 * @param {String} message
 * @param {Number|Object} line
 * @param {Number} [column]
 */
add: function() {
}

requireSpaceAfterLineComment

Requires that a line comment (//) be followed by a space.

Type: Boolean

Values: true

Example

"requireSpaceAfterLineComment": true

Valid

// A comment
/*A comment*/

Invalid

//A comment

disallowSpaceAfterLineComment

Requires that a line comment (//) not be followed by a space.

Type: Boolean

Values: true

Example

"disallowSpaceAfterLineComment": true

Valid

//A comment
/* A comment*/

Invalid

// A comment

disallowAnonymousFunctions

Requires that a function expression be named.

Type: Boolean

Values: true

Example

"disallowAnonymousFunctions": true

Valid

var a = function foo(){

};

$('#foo').click(function bar(){

};)

Invalid

var a = function(){

};

$('#foo').click(function(){

};)

requireAnonymousFunctions

Requires that a function expression be anonymous.

Type: Boolean

Values: true

Example

"requireAnonymousFunctions": true

Valid

var a = function(){

};

$('#foo').click(function(){

};)

Invalid

var a = function foo(){

};

$('#foo').click(function bar(){

};)

disallowNewlineBeforeBlockStatements

Disallows newline before opening curly brace of all block statements.

Type: Boolean

Values: true

Example

"disallowNewlineBeforeBlockStatements": true

Valid

function good(){
    var obj = {
        val: true
    };

    return {
        data: obj
    };
}

if (cond){
    foo();
}

for (var e in elements){
    bar(e);
}

while (cond){
    foo();
}

Invalid

function bad()
{
    var obj =
    {
        val: true
    };

    return {
        data: obj
    };
}

if (cond)
{
    foo();
}

for (var e in elements)
{
    bar(e);
}

while (cond)
{
    foo();
}

requireNewlineBeforeBlockStatements

Requires newline before opening curly brace of all block statements.

Type: Boolean

Values: true

Example

"requireNewlineBeforeBlockStatements": true

Valid

function good()
{
    var obj =
    {
        val: true
    };

    return {
        data: obj
    };
}

if (cond)
{
    foo();
}

for (var e in elements)
{
    bar(e);
}

while (cond)
{
    foo();
}

Invalid

function bad(){
    var obj = {
        val: true
    };

    return {
        data: obj
    };
}

if (cond){
    foo();
}

for (var e in elements){
    bar(e);
}

while (cond){
    foo();
}

Removed Rules

~~disallowLeftStickedOperators~~

Use the following rules instead:

• requireSpaceBeforeBinaryOperators
• requireSpaceBeforePostfixUnaryOperators
• requireSpacesInConditionalExpression

~~disallowRightStickedOperators~~

Use the following rules instead:

• requireSpaceAfterBinaryOperators
• requireSpaceAfterPrefixUnaryOperators
• requireSpacesInConditionalExpression

~~requireLeftStickedOperators~~

Use the following rules instead:

• disallowSpaceBeforeBinaryOperators
• disallowSpaceBeforePostfixUnaryOperators
• disallowSpacesInConditionalExpression

~~requireRightStickedOperators~~

Use the following rules instead:

• disallowSpaceAfterBinaryOperators
• disallowSpaceAfterPrefixUnaryOperators
• disallowSpacesInConditionalExpression

Browser Usage

The npm package contains a file named jscs-browser.js (since version 1.5.7), which is a browser compatible version of jscs.

If you'd like to generate this file yourself, run npm run browserify after cloning this repo.

Use jscs-browser.js on your page as follows:

<script src="jscs-browser.js"></script>
<script>
    var checker = new JscsStringChecker();
    checker.registerDefaultRules();
    checker.configure({disallowMultipleVarDecl: true});
    var errors = checker.checkString('var x, y = 1;');
    errors.getErrorList().forEach(function(error) {
        console.log(errors.explainError(error));
    });
</script>