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@stylistic/

array-bracket-spacing

A number of style guides require or disallow spaces between array brackets and other tokens. This rule applies to both array literals and destructuring assignments (ECMAScript 6).

js
/*eslint-env es6*/

var arr = [ 'foo', 'bar' ];
var [ x, y ] = z;

var arr = ['foo', 'bar'];
var [x,y] = z;

Rule Details

This rule enforces consistent spacing inside array brackets.

Options

This rule has a string option:

  • "never" (default) disallows spaces inside array brackets
  • "always" requires one or more spaces or newlines inside array brackets

This rule has an object option for exceptions to the "never" option:

  • "singleValue": true requires one or more spaces or newlines inside brackets of array literals that contain a single element
  • "objectsInArrays": true requires one or more spaces or newlines between brackets of array literals and braces of their object literal elements [ { or } ]
  • "arraysInArrays": true requires one or more spaces or newlines between brackets of array literals and brackets of their array literal elements [ [ or ] ]

This rule has an object option for exceptions to the "always" option:

  • "singleValue": false disallows spaces inside brackets of array literals that contain a single element
  • "objectsInArrays": false disallows spaces between brackets of array literals and braces of their object literal elements [{ or }]
  • "arraysInArrays": false disallows spaces between brackets of array literals and brackets of their array literal elements [[ or ]]

This rule has built-in exceptions:

  • "never" (and also the exceptions to the "always" option) allows newlines inside array brackets, because this is a common pattern
  • "always" does not require spaces or newlines in empty array literals []

never

Examples of incorrect code for this rule with the default "never" option:

js
/*eslint @stylistic/array-bracket-spacing: ["error", "never"]*/
/*eslint-env es6*/

var arr = [
'foo', 'bar'
];
var arr = ['foo', 'bar'
];
var arr = [
['foo'], 'bar'];
var arr = [[
'foo'
], 'bar'];
var arr = [
'foo',
'bar' ]; var [
x, y
] = z;
var [
x,y
] = z;
var [
x, ...y
] = z;
var [
,,x,
] = z;
incorrect

Examples of correct code for this rule with the default "never" option:

js
/*eslint @stylistic/array-bracket-spacing: ["error", "never"]*/
/*eslint-env es6*/

var arr = [];
var arr = ['foo', 'bar', 'baz'];
var arr = [['foo'], 'bar', 'baz'];
var arr = [
  'foo',
  'bar',
  'baz'
];
var arr = ['foo',
  'bar'
];
var arr = [
  'foo',
  'bar'];

var [x, y] = z;
var [x,y] = z;
var [x, ...y] = z;
var [,,x,] = z;
correct

always

Examples of incorrect code for this rule with the "always" option:

js
/*eslint @stylistic/array-bracket-spacing: ["error", "always"]*/
/*eslint-env es6*/

var arr = 
[
'foo', 'bar'
]
;
var arr =
[
'foo', 'bar' ];
var arr = [
[
'foo'
]
, 'bar' ];
var arr =
[
'foo',
'bar' ]; var arr = [ 'foo', 'bar'
]
;
var
[
x, y
]
= z;
var
[
x,y
]
= z;
var
[
x, ...y
]
= z;
var
[
,,x,
]
= z;
incorrect

Examples of correct code for this rule with the "always" option:

js
/*eslint @stylistic/array-bracket-spacing: ["error", "always"]*/
/*eslint-env es6*/

var arr = [];
var arr = [ 'foo', 'bar', 'baz' ];
var arr = [ [ 'foo' ], 'bar', 'baz' ];
var arr = [ 'foo',
  'bar'
];
var arr = [
  'foo',
  'bar' ];
var arr = [
  'foo',
  'bar',
  'baz'
];

var [ x, y ] = z;
var [ x,y ] = z;
var [ x, ...y ] = z;
var [ ,,x, ] = z;
correct

singleValue

Examples of incorrect code for this rule with the "always", { "singleValue": false } options:

js
/*eslint @stylistic/array-bracket-spacing: ["error", "always", { "singleValue": false }]*/

var foo = [
'foo'
];
var foo = [
'foo'];
var foo = ['foo'
];
var foo = [
1
];
var foo = [
1];
var foo = [1
];
var foo = [
[ 1, 2 ]
];
var foo = [
{ 'foo': 'bar' }
];
incorrect

Examples of correct code for this rule with the "always", { "singleValue": false } options:

js
/*eslint @stylistic/array-bracket-spacing: ["error", "always", { "singleValue": false }]*/

var foo = ['foo'];
var foo = [1];
var foo = [[ 1, 1 ]];
var foo = [{ 'foo': 'bar' }];
correct

objectsInArrays

Examples of incorrect code for this rule with the "always", { "objectsInArrays": false } options:

js
/*eslint @stylistic/array-bracket-spacing: ["error", "always", { "objectsInArrays": false }]*/

var arr = [
{ 'foo': 'bar' }
];
var arr = [
{
'foo': 'bar' }
]
incorrect

Examples of correct code for this rule with the "always", { "objectsInArrays": false } options:

js
/*eslint @stylistic/array-bracket-spacing: ["error", "always", { "objectsInArrays": false }]*/

var arr = [{ 'foo': 'bar' }];
var arr = [{
  'foo': 'bar'
}];
correct

arraysInArrays

Examples of incorrect code for this rule with the "always", { "arraysInArrays": false } options:

js
/*eslint @stylistic/array-bracket-spacing: ["error", "always", { "arraysInArrays": false }]*/

var arr = [
[ 1, 2 ], 2, 3, 4 ];
var arr = [
[ 1, 2 ], 2, [ 3, 4 ]
];
incorrect

Examples of correct code for this rule with the "always", { "arraysInArrays": false } options:

js
/*eslint @stylistic/array-bracket-spacing: ["error", "always", { "arraysInArrays": false }]*/

var arr = [[ 1, 2 ], 2, 3, 4 ];
var arr = [[ 1, 2 ], 2, [ 3, 4 ]];
correct

When Not To Use It

You can turn this rule off if you are not concerned with the consistency of spacing between array brackets.

Released under the MIT License.