ESLint Stylistic

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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
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"] */  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"] */  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"] */  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"] */  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.