Disallow multiple spaces (no-multi-spaces)

Multiple spaces in a row that are not used for indentation are typically mistakes. For example:


if(foo  === "bar") {}

It’s hard to tell, but there are two spaces between foo and ===. Multiple spaces such as this are generally frowned upon in favor of single spaces:


if(foo === "bar") {}

Fixable: This rule is automatically fixable using the --fix flag on the command line.

Rule Details

This rule aims to disallow multiple whitespace around logical expressions, conditional expressions, declarations, array elements, object properties, sequences and function parameters.

The following patterns are considered problems:

/*eslint no-multi-spaces: 2*/

var a =  1;            /*error Multiple spaces found before '1'.*/

if(foo   === "bar") {} /*error Multiple spaces found before '==='.*/

a <<  b                /*error Multiple spaces found before 'b'.*/

var arr = [1,  2];     /*error Multiple spaces found before '2'.*/

a ?  b: c              /*error Multiple spaces found before 'b'.*/

The following patterns are not considered problems:

/*eslint no-multi-spaces: 2*/

var a = 1;

if(foo === "bar") {}

a << b

var arr = [1, 2];

a ? b: c

Exceptions

Some rules, like key-spacing in one of its alignment modes, might require multiple spaces in some instances. To support this case, this rule accepts an options object with a property named exceptions. The exceptions object expects property names to be AST node types as defined by ESTree. The easiest way to determine the node types for exceptions is to use the online demo.

You can ignore certain parts of your code by setting node types as properties on the exceptions object with a value of true. By default, all node types are false except for Property, which is true by default in order to skip properties.

With this option, The following patterns are not considered problems:

/* eslint no-multi-spaces: 2 */
/* eslint key-spacing: [2, { align: "value" }] */

var obj = {
    first:  "first",
    second: "second"
};

/* eslint no-multi-spaces: [2, { exceptions: { "BinaryExpression": true } }] */
var a = 1  *  2;

The default Property exception can be disabled by setting it to false, so the following pattern is considered a warning:

/* eslint no-multi-spaces: [2, { exceptions: { "Property": false } }] */
/* eslint key-spacing: [2, { align: "value" }] */

var obj = {
    first:  "first",  /*error Multiple spaces found before '"first"'.*/
    second: "second"
};

You may wish to align variable declarations or import declarations with spaces. You can add exceptions for these cases:

/* eslint no-multi-spaces: [2, { exceptions: { "VariableDeclarator": true } }] */

var someVar      = 'foo';
var someOtherVar = 'barBaz';

/* eslint no-multi-spaces: [2, { exceptions: { "ImportDeclaration": true } }] */

import mod          from 'mod';
import someOtherMod from 'some-other-mod';

When Not To Use It

If you don’t want to check and disallow multiple spaces, then you should turn this rule off.

Version

This rule was introduced in ESLint 0.9.0.

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