jscs
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JavaScript Style Checker
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node-jscs [](https://travis-ci.org/mdevils/node-jscs)
=========
JSCS — JavaScript Code Style.
`jscs` is a code style checker. `jscs` can check cases, which are not implemeted in jshint,
but it does not duplicate `jshint` functionality, so you should use `jscs` and `jshint` together.
Friendly packages
-----------------
* JSCS Grunt Task: https://github.com/gustavohenke/grunt-jscs-checker
Installation
------------
`jscs` can be installed using `npm`:
```
npm install jscs
```
To run `jscs`, you can use the following command from the project root:
```
./node_modules/.bin/jscs path[ path[...]]
```
Configuration
-------------
`jscs` is configured using `.jscs.json` file, located in the project root.
Example configuration:
```javascript
{
/*
Option: requireCurlyBraces
Requires curly braces after statements.
Valid example:
if (x) {
x++;
}
Invalid example:
if (x) x++;
*/
"requireCurlyBraces": ["if", "else", "for", "while", "do"],
/*
Option: requireSpaceAfterKeywords
Requires space after keyword.
Valid example:
return true;
Invalid example:
if(x) {
x++;
}
*/
"requireSpaceAfterKeywords": ["if", "else", "for", "while", "do", "switch", "return"],
/*
Option: disallowSpaceAfterKeywords
Disallows space after keyword.
Valid example:
if(x > y) {
y++;
}
*/
"disallowSpaceAfterKeywords": ["if", "else", "for", "while", "do", "switch"],
/*
Option: requireSpacesInFunctionExpression
Requires space before () or {} in function declarations.
Valid examples:
function () {}
function a () {}
Invalid examples:
function() {}
function (){}
*/,
"requireSpacesInFunctionExpression": { "beforeOpeningRoundBrace": true, "beforeOpeningCurlyBrace": true },
/*
Option: disallowSpacesInFunctionExpression
Disallows space before () or {} in function declarations.
Valid examples:
function(){}
function a(){}
Invalid examples:
function () {}
function a (){}
*/,
"disallowSpacesInFunctionExpression": { "beforeOpeningRoundBrace": true, "beforeOpeningCurlyBrace": true },
/*
Option: disallowMultipleVarDecl
Disallows multiple var declaration (except for-loop).
Valid example:
var x = 1;
var y = 2;
for (var i = 0, j = arr.length; i < j; i++) {}
Invalid example:
var x = 1,
y = 2;
*/
"disallowMultipleVarDecl": true,
/*
Option: requireMultipleVarDecl
Requires multiple var declaration.
Valid example:
var x = 1,
y = 2;
Invalid example:
var x = 1;
var y = 2;
*/
"requireMultipleVarDecl": true,
/*
Option: disallowSpacesInsideObjectBrackets
Disallows space after opening object curly brace and before closing.
Valid example:
var x = {a: 1};
Invalid example:
var x = { a: 1 };
*/
"disallowSpacesInsideObjectBrackets": true,
/*
Option: disallowSpacesInsideArrayBrackets
Disallows space after opening array square bracket and before closing.
Valid example:
var x = [1];
Invalid example:
var x = [ 1 ];
*/
"disallowSpacesInsideArrayBrackets": true,
/*
Option: disallowSpacesInsideParentheses
Disallows space after opening round bracket and before closing.
Valid example:
var x = (1 + 2) * 3;
Invalid example:
var x = ( 1 + 2 ) * 3;
*/
"disallowSpacesInsideParentheses": true,
/*
Option: requireSpacesInsideObjectBrackets
Possible values: "all" for strict mode, "allButNested" ignores closing brackets in a row.
Requires space after opening object curly brace and before closing.
Valid example for mode "all":
var x = { a: { b: 1 } };
Valid example for mode "allButNested":
var x = { a: { b: 1 }};
Invalid example:
var x = {a: 1};
*/
"requireSpacesInsideObjectBrackets": "all",
/*
Option: requireSpacesInsideArrayBrackets
Possible values: "all" for strict mode, "allButNested" ignores closing brackets in a row.
Requires space after opening array square bracket and before closing.
Valid example for mode "all":
var x = [ 1 ];
Valid example for mode "allButNested":
var x = [[ 1 ], [ 2 ]];
Invalid example:
var x = [1];
*/
"requireSpacesInsideArrayBrackets": "all",
/*
Option: disallowQuotedKeysInObjects
Disallows quoted keys in object if possible.
Valid example:
var x = {a: 1};
Invalid example:
var x = {'a': 1};
*/
"disallowQuotedKeysInObjects": true,
/*
Option: disallowSpaceAfterObjectKeys
Disallows space after object keys.
Valid example:
var x = {a: 1};
Invalid example:
var x = {a : 1};
*/
"disallowSpaceAfterObjectKeys": true,
/*
Option: requireSpaceAfterObjectKeys
Requires space after object keys.
Valid example:
var x = {a : 1};
Invalid example:
var x = {a: 1};
*/
"requireSpaceAfterObjectKeys": true,
/*
Option: requireAlignedObjectValues
Possible values:
"all" for strict mode,
"skipWithFunction" ignores objects if one of the property values is a function expression,
"skipWithLineBreak" ignores objects if there are line breaks between properties
Requires proper alignment in object literals.
Valid example:
var x = {
a : 1,
bcd : 2,
ef : 'str'
};
Invalid example:
var x = {
a : 1,
bcd : 2,
ef : 'str'
};
*/
"requireAlignedObjectValues": "all",
/*
Option: disallowLeftStickedOperators
Disallows sticking operators to the left.
Valid example:
x = y ? 1 : 2;
Invalid example:
x = y? 1 : 2;
*/
"disallowLeftStickedOperators": ["?", "+", "-", "/", "*", "=", "==", "===", "!=", "!==", ">", ">=", "<", "<="],
/*
Option: requireRightStickedOperators
Requires sticking operators to the right.
Valid example:
x = !y;
Invalid example:
x = ! y;
*/
"requireRightStickedOperators": ["!"],
/*
Option: disallowRightStickedOperators
Disallows sticking operators to the right.
Valid example:
x = y + 1;
Invalid example:
x = y +1;
*/
"disallowRightStickedOperators": ["?", "+", "/", "*", ":", "=", "==", "===", "!=", "!==", ">", ">=", "<", "<="],
/*
Option: requireLeftStickedOperators
Requires sticking operators to the left.
Valid example:
x = [1, 2];
Invalid example:
x = [1 , 2];
*/
"requireLeftStickedOperators": [","],
/*
Option: disallowSpaceAfterPrefixUnaryOperators
Requires sticking unary operators to the right.
Valid example:
x = !y; y = ++z;
Invalid example:
x = ! y; y = ++ z;
*/
"disallowSpaceAfterPrefixUnaryOperators": ["++", "--", "+", "-", "~", "!"],
/*
Option: requireSpaceAfterPrefixUnaryOperators
Disallows sticking unary operators to the right.
Valid example:
x = ! y; y = ++ z;
Invalid example:
x = !y; y = ++z;
*/
"requireSpaceAfterPrefixUnaryOperators": ["++", "--", "+", "-", "~", "!"],
/*
Option: disallowSpaceBeforePostfixUnaryOperators
Requires sticking unary operators to the left.
Valid example:
x = y++; y = z--;
Invalid example:
x = y ++; y = z --;
*/
"disallowSpaceBeforePostfixUnaryOperators": ["++", "--"],
/*
Option: requireSpaceBeforePostfixUnaryOperators
Disallows sticking unary operators to the left.
Valid example:
x = y ++; y = z --;
Invalid example:
x = y++; y = z--;
*/
"requireSpaceBeforePostfixUnaryOperators": ["++", "--"],
/*
Option: disallowSpaceBeforeBinaryOperators
Requires sticking binary operators to the left.
Valid example:
x+ y;
Invalid example:
x + y;
*/
"disallowSpaceBeforeBinaryOperators": ["+", "-", "/", "*", "=", "==", "===", "!=", "!=="],
/*
Option: requireSpaceBeforeBinaryOperators
Disallows sticking binary operators to the left.
Valid example:
x !== y;
Invalid example:
x!== y;
*/
"requireSpaceBeforeBinaryOperators": ["+", "-", "/", "*", "=", "==", "===", "!=", "!=="],
/*
Option: disallowSpaceAfterBinaryOperators
Requires sticking binary operators to the right.
Valid example:
x +y;
Invalid example:
x+ y;
*/
"disallowSpaceAfterBinaryOperators": ["+", "-", "/", "*", "=", "==", "===", "!=", "!=="],
/*
Option: requireSpaceAfterBinaryOperators
Disallows sticking binary operators to the right.
Valid example:
x + y;
Invalid example:
x +y;
*/
"requireSpaceAfterBinaryOperators": ["+", "-", "/", "*", "=", "==", "===", "!=", "!=="],
/*
Option: disallowImplicitTypeConversion
Disallows implicit type conversion.
Valid example:
x = Boolean(y);
x = Number(y);
x = String(y);
x = s.indexOf('.') !== -1;
Invalid example:
x = !!y;
x = +y;
x = '' + y;
x = ~s.indexOf('.');
*/
"disallowImplicitTypeConversion": ["numeric", "boolean", "binary", "string"],
/*
Option: disallowKeywords
Disallows usage of specified keywords.
Invalid example:
with (x) {
prop++;
}
*/
"disallowKeywords": ["with"],
/*
Option: disallowMultipleLineBreaks
Disallows multiple blank lines in a row.
Invalid example:
var x = 1;
x++;
*/
"disallowMultipleLineBreaks": true,
/*
Option: disallowKeywordsOnNewLine
Disallows placing keywords on a new line.
Valid example:
if (x < 0) {
x++;
} else {
x--;
}
Invalid example:
if (x < 0) {
x++;
}
else {
x--;
}
*/
"disallowKeywordsOnNewLine": ["else"],
/*
Option: requireKeywordsOnNewLine
Requires placing keywords on a new line.
Valid example:
if (x < 0) {
x++;
}
else {
x--;
}
Invalid example:
if (x < 0) {
x++;
} else {
x--;
}
*/
"requireKeywordsOnNewLine": ["else"],
/*
Option: requireLineFeedAtFileEnd
Requires placing line feed at file end.
*/
"requireLineFeedAtFileEnd": true,
/*
Option: safeContextKeyword
Option to check "var that = this" expressions
Valid example:
var that = this;
Invalid example:
var _this = this;
*/
"safeContextKeyword": "that"
/*
Option: validateJSDoc
Enables jsdoc validation.
Option: validateJSDoc.checkParamNames
Ensures param names in jsdoc and in function declaration are equal.
Option: validateJSDoc.requireParamTypes
Ensures params in jsdoc contains type.
Option: validateJSDoc.checkRedundantParams
Reports redundant params in jsdoc.
*/
"validateJSDoc": {
"checkParamNames": true,
"checkRedundantParams": true,
"requireParamTypes": true
},
/*
Option: excludeFiles
Disables style checking for specified paths.
*/
"excludeFiles": ["node_modules/**"]
}
```
Browser Usage
-------------
File `jscs-browser.js` contains browser-compatible version of `jscs`.
Download and include `jscs-browser.js` into your page.
Example:
```html
<script type="text/javascript" src="jscs-browser.js"></script>
<script type="text/javascript">
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>
```