Perfectionist

sort-objects

Enforce sorted objects.

By adhering to this rule, developers can ensure that object keys are consistently sorted, leading to cleaner and more maintainable code. This rule promotes a standardized key ordering across objects, making it easier to navigate and understand the structure of objects within the codebase.

It’s safe. The rule considers spread elements in objects and does not break component functionality.

Important

If you use the sort-keys rule, it is highly recommended to disable it to avoid conflicts.

Try it out

const event = {
description: 'Annual conference discussing the latest in technology.',
organizer: {
email: 'charlie.brown@protonmail.com',
phone: '555-1234',
name: 'Charlie Brown',
},
title: 'Tech Conference 2023',
schedule: [
{
speaker: null,
time: '09:00 AM',
activity: 'Registration',
},
{
speaker: 'Jane Doe',
time: '10:00 AM',
activity: 'Opening Keynote',
},
{
activity: 'Tech Trends 2023',
time: '11:00 AM',
speaker: 'Alice Johnson',
}
],
location: {
state: 'CA',
address: '123 Tech Street',
city: 'San Francisco',
postalCode: '94103',
country: 'USA',
venue: 'Tech Center',
},
date: new Date('2023-09-15'),
status: 'upcoming',
}

Options

This rule accepts an options object with the following properties:

type

default: 'alphabetical'

Specifies the sorting method.

  • 'alphabetical' — Sort items alphabetically (e.g., “a” < “b” < “c”) using localeCompare.
  • 'natural' — Sort items in a natural order (e.g., “item2” < “item10”).
  • 'line-length' — Sort items by code line length (shorter lines first).
  • 'custom' — Sort items using the alphabet specified in the alphabet option.
  • 'unsorted' — Do not sort items. grouping and newlines behavior are still enforced.

order

default: 'asc'

Specifies whether to sort items in ascending or descending order.

  • 'asc' — Sort items in ascending order (A to Z, 1 to 9).
  • 'desc' — Sort items in descending order (Z to A, 9 to 1).

fallbackSort

type:

{
  type: 'alphabetical' | 'natural' | 'line-length' | 'custom' | 'subgroup-order' | 'unsorted'
  order?: 'asc' | 'desc'
}
default: { type: 'unsorted' }

Specifies fallback sort options for elements that are equal according to the primary sort type.

You can also sort by subgroup order (nested groups in the groups option) using subgroup-order.

Example: enforce alphabetical sort between two elements with the same length.

{
  type: 'line-length',
  order: 'desc',
  fallbackSort: { type: 'alphabetical', order: 'asc' }
}

alphabet

default: ''

Used only when the type option is set to 'custom'. Specifies the custom alphabet for sorting.

Use the Alphabet utility class from eslint-plugin-perfectionist/alphabet to quickly generate a custom alphabet.

Example: 0123456789abcdef...

ignoreCase

default: true

Specifies whether sorting should be case-sensitive.

  • true — Ignore case when sorting alphabetically or naturally (e.g., “A” and “a” are the same).
  • false — Consider case when sorting (e.g., “a” comes before “A”).

specialCharacters

default: keep

Specifies whether to trim, remove, or keep special characters before sorting.

  • 'keep' — Keep special characters when sorting (e.g., “_a” comes before “a”).
  • 'trim' — Trim special characters when sorting alphabetically or naturally (e.g., “_a” and “a” are the same).
  • 'remove' — Remove special characters when sorting (e.g., “/a/b” and “ab” are the same).

locales

default: 'en-US'

Specifies the sorting locales. Refer To String.prototype.localeCompare() - locales.

  • string — A BCP 47 language tag (e.g. 'en', 'en-US', 'zh-CN').
  • string[] — An array of BCP 47 language tags.

partitionByComment

default: false

Enables the use of comments to separate the keys of objects into logical groups. This can help in organizing and maintaining large objects by creating partitions based on comments.

  • true — All comments will be treated as delimiters, creating partitions.
  • false — Comments will not be used as delimiters.
  • RegExpPattern = string | { pattern: string; flags: string} — A regexp pattern to specify which comments should act as delimiters.
  • RegExpPattern[] — A list of regexp patterns to specify which comments should act as delimiters.
  • { block: boolean | RegExpPattern | RegExpPattern[]; line: boolean | RegExpPattern | RegExpPattern[] } — Specify which block and line comments should act as delimiters.

partitionByNewLine

default: false

When true, the rule will not sort the object’s keys if there is an empty line between them. This helps maintain the defined order of logically separated groups of keys.

const user = {
  // Group 1
  firstName: 'John',
  lastName: 'Doe',

  // Group 2
  age: 30,
  birthDate: '1990-01-01',

  // Group 3
  email: 'john.doe@example.com',
  phone: '555-555-5555'
};

Each group of keys (separated by empty lines) is treated independently, and the order within each group is preserved.

newlinesBetween

type: number | 'ignore'

default: 'ignore'

Specifies how to handle newlines between groups.

  • 'ignore' — Do not report errors related to newlines.
  • 0 — No newlines are allowed.
  • Any other number — Enforce this number of newlines between each group.

You can also enforce the newline behavior between two specific groups through the groups option.

This option is only applicable when partitionByNewLine is false.

newlinesInside

type: number | 'ignore' | 'newlinesBetween'

default: 'newlinesBetween'

Specifies how to handle newlines inside groups.

  • 'ignore' — Do not report errors related to newlines.
  • 'newlinesBetween' — [DEPRECATED] If newlinesBetween is 'ignore', then 'ignore', otherwise 0.
  • 0 — No newlines are allowed.
  • Any other number — Enforce this number of newlines between each element of the same group.

You can also enforce the newline behavior inside a given group through the groups or customGroups options.

This option is only applicable when partitionByNewLine is false.

styledComponents

default: true

Specifies whether this rule should be applied to styled-components like libraries or style JSX attribute.

  • true — Apply the rule to styled-components.
  • false — Disable the rule for styled-components.

useConfigurationIf

type:

{
  allNamesMatchPattern?:
    | string
    | string[]
    | { pattern: string; flags: string }
    | { pattern: string; flags: string }[]
  callingFunctionNamePattern?:
    | string
    | string[]
    | { pattern: string; flags?: string; scope?: 'shallow' | 'deep' }
    | { pattern: string; flags?: string; scope?: 'shallow' | 'deep' }[]
  declarationMatchesPattern?:
    | string
    | string[]
    | { pattern: string; flags?: string; scope?: 'shallow' | 'deep' }
    | { pattern: string; flags?: string; scope?: 'shallow' | 'deep' }[]
  declarationCommentMatchesPattern?:
    | string
    | string[]
    | { pattern: string; flags?: string; scope?: 'shallow' | 'deep' }
    | { pattern: string; flags?: string; scope?: 'shallow' | 'deep' }[]
  objectType?: 'destructured' | 'non-destructured'
  hasNumericKeysOnly?: boolean
}
default: {}

Specifies filters to match a particular options configuration for a given object.

The first matching options configuration will be used. If no configuration matches, the default options configuration will be used.

  • allNamesMatchPattern — A regexp pattern that all object keys must match.

Example configuration:

{
  'perfectionist/sort-objects': [
    'error',
    {
      groups: ['r', 'g', 'b'], // Sort colors by RGB
      customGroups: [
        {
          groupName: 'r',
          elementNamePattern: '^r$',
        },
        {
          groupName: 'g',
          elementNamePattern: '^g$',
        },
        {
          groupName: 'b',
          elementNamePattern: '^b$',
        },
      ],
      useConfigurationIf: {
        allNamesMatchPattern: '^r|g|b$',
      },
    },
    {
      type: 'alphabetical' // Fallback configuration
    }
  ],
}
  • callingFunctionNamePattern — A regexp pattern for matching objects that are passed as arguments to a function with a specific name. With scope: 'deep', this setting will also match any object found at any depth within the arguments of the function call.

Example configuration:

{
  'perfectionist/sort-objects': [
    'error',
    {
      type: 'unsorted', // Don't sort objects passed to createSlice
      useConfigurationIf: {
        callingFunctionNamePattern: '^createSlice$',
      },
    },
    {
      type: 'alphabetical' // Fallback configuration
    }
  ],
}
  • declarationMatchesPattern — A regexp pattern that the object’s declaration name must match. With scope: 'deep', this setting will also match to any object found at any depth within the declaration.

Example configuration:

{
  'perfectionist/sort-objects': [
    'error',
    {
      type: 'unsorted', // Do not sort metadata objects
      useConfigurationIf: {
        declarationMatchesPattern: '*metadata$',
      },
    },
    {
      type: 'alphabetical' // Fallback configuration
    }
  ],
}
  • declarationCommentMatchesPattern — A regexp pattern to specify which comments above the object declaration should match. With scope: 'deep', this setting will also match any object found at any depth within the arguments of the function call.

Example configuration:

{
  'perfectionist/sort-objects': [
    'error',
    {
      type: 'unsorted', // Don't sort objects with a "do not sort" comment
      useConfigurationIf: {
        declarationCommentMatchesPattern: '^do not sort$',
      },
    },
    {
      type: 'alphabetical' // Fallback configuration
    }
  ],
}
  • objectType — Specifies what type of object to match.

Example configuration:

{
  'perfectionist/sort-objects': [
    'error',
    {
      type: 'unsorted', // Don't sort destructured objects
      useConfigurationIf: {
        objectType: 'destructured',
      },
    },
    {
      type: 'alphabetical' // Fallback configuration
    }
  ],
}
  • hasNumericKeysOnly — If true, matches only objects that have exclusively numeric keys.

This option only detects unquoted numeric literal keys (e.g., 1, 42). Quoted strings like "1", array-wrapped keys like [1], or computed expressions are not detected as numeric keys.

Example configuration:

{
  'perfectionist/sort-objects': [
    'error',
    {
      type: 'natural', // Sort numeric keys naturally (by numeric value)
      useConfigurationIf: {
        hasNumericKeysOnly: true,
      },
    },
    {
      type: 'alphabetical' // Fallback configuration
    }
  ],
}

groups

type:

  Array<
    | string
    | string[]
    | { newlinesBetween: number | 'ignore' }
    | {
        group: string | string[];
        type?: 'alphabetical' | 'natural' | 'line-length' | 'custom' | 'unsorted';
        order?: 'asc' | 'desc';
        fallbackSort?: { type: string; order?: 'asc' | 'desc' };
        newlinesInside?: number | 'ignore';
      }
  >
default: []

Specifies a list of object keys groups for sorting. Groups help organize object keys into categories, making your objects more readable and maintainable.

Each property will be assigned a single group specified in the groups option (or the unknown group if no match is found). The order of items in the groups option determines how groups are ordered.

Within a given group, members will be sorted according to the type, order, ignoreCase, etc. options.

Individual groups can be combined together by placing them in an array. The order of groups in that array does not matter. All members of the groups in the array will be sorted together as if they were part of a single group.

Predefined groups are characterized by a single selector and potentially multiple modifiers. You may enter modifiers in any order, but the selector must always come at the end.

Example

let user = {
  firstName: "John", // unknown
  lastName: "Doe",  // unknown
  username: "john_doe",  // unknown
  job: {            // multiline-member
    // Stuff about job
  },
  localization: {   // multiline-member
    // Stuff about localization
  }
}

groups option configuration:

{
  groups: [
    'unknown',
    'method',
    'multiline-member',
  ]
}

Methods

  • Selectors: 'method', 'member'.
  • Modifiers: 'multiline'.
  • Example: 'multiline-method', 'method', 'member'.

Properties

  • Selectors: 'property', 'member'.
  • Modifiers: 'multiline'.
  • Example: 'multiline-property', 'property', 'member'.
The unknown group

Members that don’t fit into any group specified in the groups option will be placed in the unknown group. If the unknown group is not specified in the groups option, it will automatically be added to the end of the list.

Important notes

Behavior when multiple groups match an element

The lists of modifiers above are sorted by importance, from most to least important. In case of multiple groups matching an element, the following rules will be applied:

  1. The group with the most modifiers matching will be selected.
  2. If modifiers quantity is the same, order will be chosen based on modifier importance as listed above.

Example :

interface Test {
  multilineMethod: () => {
      property: string;
    }
}

'multilineMethod' can be matched by the following groups, from most to least important:

  • 'multiline-method'.
  • 'method'.
  • 'multiline-member'.
  • 'member'.
  • 'unknown'.

Group with overridden settings

You may directly override options for a specific group by using an object with the group property and other option overrides.

  • type — Overrides the type option for that group.
  • order — Overrides the order option for that group.
  • fallbackSort — Overrides the fallbackSort option for that group.
  • newlinesInside — Overrides the newlinesInside option for that group.
{
  groups: [
    'method',
    { group: 'multiline-member', type: 'unsorted' }, // Elements from this group will not be sorted
  ]
}
Newlines between groups

You may place newlinesBetween objects between your groups to enforce the newline behavior between two specific groups.

See the newlinesBetween option.

This feature is only applicable when partitionByNewLine is false.

{
  newlinesBetween: 1,
  groups: [
    'a',
    { newlinesBetween: 0 }, // Overrides the global newlinesBetween option
    'b',
  ]
}

customGroups

Migrating from the old API

Support for the object-based customGroups option is deprecated.

Migrating from the old to the current API is easy:

Old API:

{
  "key1": "value1",
  "key2": "value2"
}

Current API:

[
  {
    "groupName": "key1",
    "elementNamePattern": "value1"
  },
  {
    "groupName": "key2",
    "elementNamePattern": "value2"
  }
]

type: Array<CustomGroupDefinition | CustomGroupAnyOfDefinition>

default: []

Defines custom groups to match specific object keys.

A custom group definition may follow one of the two following interfaces:

interface CustomGroupDefinition {
  groupName: string
  type?: 'alphabetical' | 'natural' | 'line-length' | 'unsorted'
  order?: 'asc' | 'desc'
  fallbackSort?: { type: string; order?: 'asc' | 'desc' }
  newlinesInside?: number | 'ignore'
  selector?: string
  modifiers?: string[]
  elementNamePattern?: string | string[] | { pattern: string; flags?: string } | { pattern: string; flags?: string }[]
  elementValuePattern?: string | string[] | { pattern: string; flags?: string } | { pattern: string; flags?: string }[]
}

An object will match a CustomGroupDefinition group if it matches all the filters of the custom group’s definition.

or:

interface CustomGroupAnyOfDefinition {
  groupName: string
  type?: 'alphabetical' | 'natural' | 'line-length' | 'unsorted'
  order?: 'asc' | 'desc'
  fallbackSort?: { type: string; order?: 'asc' | 'desc' }
  newlinesInside?: number | 'ignore'
  anyOf: Array<{
      selector?: string
      modifiers?: string[]
      elementNamePattern?: string | string[] | { pattern: string; flags?: string } | { pattern: string; flags?: string }[]
      elementValuePattern?: string | string[] | { pattern: string; flags?: string } | { pattern: string; flags?: string }[]
  }>
}

An object will match a CustomGroupAnyOfDefinition group if it matches all the filters of at least one of the anyOf items.

Attributes

  • groupName — The group’s name, which needs to be put in the groups option.
  • selector — Filter on the selector of the element.
  • modifiers — Filter on the modifiers of the element. (All the modifiers of the element must be present in that list)
  • elementNamePattern — If entered, will check that the name of the element matches the pattern entered.
  • elementValuePattern — Only for non-function properties. If entered, will check that the value of the property matches the pattern entered.
  • type — Overrides the type option for that custom group.
  • order — Overrides the order option for that custom group.
  • fallbackSort — Overrides the fallbackSort option for that custom group.
  • newlinesInside — Overrides the newlinesInside option for that custom group.

Match importance

The customGroups list is ordered: The first custom group definition that matches an element will be used.

Custom groups have a higher priority than any predefined group.

Example

Put all properties starting with id and name at the top, combine and sort metadata and multiline properties at the bottom. Anything else is put in the middle.

let user = {
  id: "id",                 // top
  name: "John",               // top
  age: 42,                // unknown
  isAdmin: true,           // unknown
  lastUpdated_metadata: null, // bottom
  localization: {            // multiline-member
    // Stuff about localization
  },
  version_metadata: "1"   // bottom
}

groups and customGroups configuration:

 {
   groups: [
+    'top',
     'unknown',
+    ['multiline-member', 'bottom'] 
   ],
+  customGroups: [                           
+    {                                       
+       groupName: 'top',
+       selector: 'property',
+       elementNamePattern: '^(?:id|name)$',
+    },
+    {                                       
+       groupName: 'bottom',
+       selector: 'property',
+       elementNamePattern: '.+_metadata$',
+    }                                       
+  ]                                         
 }

Usage

// .eslintrc.js
module.exports = {
plugins: [
'perfectionist',
],
rules: {
'perfectionist/sort-objects': [
'error',
{
type: 'alphabetical',
order: 'asc',
fallbackSort: { type: 'unsorted' },
ignoreCase: true,
specialCharacters: 'keep',
partitionByComment: false,
partitionByNewLine: false,
newlinesBetween: 'ignore',
newlinesInside: 'ignore',
styledComponents: true,
useConfigurationIf: {},
groups: [],
customGroups: [],
},
],
},
}

Version

This rule was introduced in v0.6.0.

Resources

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