sort-sets

type

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

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

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

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

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

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

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

Enables the use of comments to separate the members of sets into logical groups. This can help in organizing and maintaining large sets 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

When true, the rule will not sort the members of a set if there is an empty line between them. This helps maintain the defined order of logically separated groups of members.

let items = new Set([
     // Group 1
    'Drone',
    'Keyboard',
    'Mouse',
    'Smartphone',

    // Group 2
    'Laptop',
    'Monitor',
    'Smartwatch',
    'Tablet',

    // Group 3
    'Headphones',
    'Router',
  ])

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

newlinesBetween

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

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.

useConfigurationIf

{
  allNamesMatchPattern?:
    | string
    | string[]
    | { pattern: string; flags: string }
    | { pattern: string; flags: string }[]
}

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

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 set values must match.

Example configuration:

{
  'perfectionist/sort-sets': [
    'error',
    {
      groups: ['r', 'g', 'b'], // Sort colors by RGB
      customGroups: [
        {
          elementNamePattern: '^r$',
          groupName: 'r',
        },
        {
          elementNamePattern: '^g$',
          groupName: 'g',
        },
        {
          elementNamePattern: '^b$',
          groupName: 'b',
        },
      ],
      useConfigurationIf: {
        allNamesMatchPattern: '^r|g|b$',
      },
    },
    {
      type: 'alphabetical' // Fallback configuration
    }
  ],
}

groups

  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';
      }
  >

Specifies a list of groups for sorting. Groups help organize elements into categories.

Each element 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 selector.

{
  groups: [
    'literal',
    { group: 'spread', type: 'unsorted' }, // Elements from this group will not be sorted
  ]
}

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

customGroups

Defines custom groups to match specific elements.

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
  elementNamePattern?: string | string[] | { pattern: string; flags?: string } | { pattern: string; flags?: string }[]
}

A set element 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
      elementNamePattern?: string | string[] | { pattern: string; flags?: string } | { pattern: string; flags?: string }[]
  }>
}

A set element will match a CustomGroupAnyOfDefinition group if it matches all the filters of at least one of the anyOf items.