eslint-plugin-perfectionist/docs/content/rules/sort-sets.mdx at b49f289e80683d96af4ca4c2e639364329598f5d · hugop95/eslint-plugin-perfectionist

title

sort-sets

description

Ensure your sets are sorted. Improve readability and maintain consistent code with this ESLint rule

shortDescription

Enforce sorted Set elements

keywords

eslint

sort set

eslint rule

coding standards

code quality

javascript linting

set sorting

import CodeExample from '../../components/CodeExample.svelte' import CodeTabs from '../../components/CodeTabs.svelte' import dedent from 'dedent'

Enforce sorted set values.

By keeping sets sorted, developers can quickly scan and verify the values, making the code more predictable and reducing the likelihood of errors. This practice simplifies debugging and enhances the overall clarity of the codebase.

Try it out

<CodeExample alphabetical={dedentconst getProductCategories = (product) => { let electronics = new Set([ 'Drone', 'Headphones', 'Keyboard', 'Laptop', 'Monitor', 'Mouse', 'Router', 'Smartphone', 'Smartwatch', 'Tablet', ]) let accessories = new Set([ 'Adapter', 'Case', 'Charger', 'Screen Protector', 'Cable', 'Battery', 'Memory Card', ]) if (electronics.has(product.name)) { return 'Electronics' } else if (accessories.has(product.name)) { return 'Accessories' } return 'Unknown' }} lineLength={dedentconst getProductCategories = (product) => { let electronics = new Set([ 'Smartphone', 'Smartwatch', 'Headphones', 'Keyboard', 'Monitor', 'Laptop', 'Router', 'Tablet', 'Drone', 'Mouse', ]) let accessories = new Set([ 'Screen Protector', 'Memory Card', 'Adapter', 'Charger', 'Battery', 'Cable', 'Case', ]) if (electronics.has(product.name)) { return 'Electronics' } else if (accessories.has(product.name)) { return 'Accessories' } return 'Unknown' }} initial={dedentconst getProductCategories = (product) => { let electronics = new Set([ 'Mouse', 'Drone', 'Smartphone', 'Keyboard', 'Tablet', 'Monitor', 'Laptop', 'Smartwatch', 'Router', 'Headphones', ]) let accessories = new Set([ 'Memory Card', 'Charger', 'Cable', 'Battery', 'Screen Protector', 'Case', 'Adapter', ]) if (electronics.has(product.name)) { return 'Electronics' } else if (accessories.has(product.name)) { return 'Accessories' } return 'Unknown' }} client:load lang="tsx" />

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:
```ts
{
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 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

_{default: false}

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

_{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.

useConfigurationIf

_{type:
```ts
{
allNamesMatchPattern?:
| string
| string[]
| { pattern: string; flags: string }
| { pattern: string; flags: string }[]
matchesAstSelector?: string
}
```} _{default: `{}`}

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$',
          groupName: 'b',
        },
      ],
      useConfigurationIf: {
        allNamesMatchPattern: '^[rgb]$',
      },
    },
    {
      type: 'alphabetical' // Fallback configuration
    }
  ],
}

matchesAstSelector — An AST selector matching an ArrayExpression ([a, b]) or NewExpression (new Array(a, b)) node. To avoid unexpected behavior, do not use :exit or :enter pseudo-selectors.

Example configuration: don't sort set elements that are declared as const variables.

{
  'perfectionist/sort-sets': [
    'error',
    {
      useConfigurationIf: {
        matchesAstSelector: 'VariableDeclaration[kind="const"] ArrayExpression',
      },
      type: 'unsorted'
    },
    {
      type: 'alphabetical' // Fallback configuration
    }
  ],
}

groups

_{type:
```ts
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: `['literal']`}

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.

Selectors

'literal' — Set elements that are not spread values.

Note: Spread elements (...array) are not sorted and act as partition boundaries. This ensures the original order of spread elements is preserved, which is important because reordering spread elements can change the iteration order of the resulting Set.

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: [
    'literal',
    { group: 'spread', 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

_{type: `Array`} _{default: `[]`}

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.

Attributes

groupName — The group's name, which needs to be put in the groups option.
selector — Filter on the selector of the element.
elementNamePattern — If entered, will check that the name of the element 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.

Usage

<CodeTabs code={[ { source: dedent` // eslint.config.js import perfectionist from 'eslint-plugin-perfectionist'

    export default [
      {
        plugins: {
          perfectionist,
        },
        rules: {
          'perfectionist/sort-sets': [
            'error',
            {
              type: 'alphabetical',
              order: 'asc',
              fallbackSort: { type: 'unsorted' },
              ignoreCase: true,
              specialCharacters: 'keep',
              partitionByComment: false,
              partitionByNewLine: false,
              newlinesBetween: 'ignore',
              newlinesInside: 'ignore',
              useConfigurationIf: {},
              groups: ['literal'],
              customGroups: [],
            },
          ],
        },
      },
    ]
  `,
  name: 'Flat Config',
  value: 'flat',
},
{
  source: dedent`
    // .eslintrc.js
    module.exports = {
      plugins: [
        'perfectionist',
      ],
      rules: {
        'perfectionist/sort-sets': [
          'error',
          {
            type: 'alphabetical',
            order: 'asc',
            fallbackSort: { type: 'unsorted' },
            ignoreCase: true,
            specialCharacters: 'keep',
            partitionByComment: false,
            partitionByNewLine: false,
            newlinesBetween: 'ignore',
            newlinesInside: 'ignore',
            useConfigurationIf: {},
            groups: ['literal'],
            customGroups: [],
          },
        ],
      },
    }
  `,
  name: 'Legacy Config',
  value: 'legacy',
},

]} type="config-type" client:load lang="tsx" />

Version

This rule was introduced in v3.4.0.

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Options

type

order

fallbackSort

alphabet

ignoreCase

specialCharacters

locales

partitionByComment

partitionByNewLine

newlinesBetween

newlinesInside

useConfigurationIf

groups

Selectors

Group with overridden settings

Newlines between groups

customGroups

Attributes

Match importance

Usage

Version

Resources

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sort-sets.mdx

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sort-sets.mdx

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Options

type

order

fallbackSort

alphabet

ignoreCase

specialCharacters

locales

partitionByComment

partitionByNewLine

newlinesBetween

newlinesInside

useConfigurationIf

groups

Selectors

Group with overridden settings

Newlines between groups

customGroups

Attributes

Match importance

Usage

Version

Resources