sort-interfaces

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' | 'unsorted'
  order?: 'asc' | 'desc'
  sortBy?: 'name' | 'value'
}

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

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.

sortBy

Controls whether sorting should be done only using the interface’s values.

• name — Use interface types keys.
• value — Use the values of properties. Non-properties will not have an enforced sort order.

Example

interface User {
  createdAt: Date
  lastLoginAt: Date
  _id: ObjectId
  groupId: ObjectId
  city: string
}

sortBy option configuration:

{
  sortBy: 'value',
}

[DEPRECATED] ignorePattern

Use the useConfigurationIf.declarationMatchesPattern option alongside type: unsorted instead.

Specifies names or patterns for interfaces that should be ignored by this rule. This can be useful if you have specific interfaces that you do not want to sort.

You can specify their names or a regexp pattern to ignore, for example: '^Component.+' to ignore all interfaces whose names begin with the word “Component”.

partitionByComment

Enables the use of comments to separate the properties of interfaces into logical groups. This can help in organizing and maintaining large interfaces by creating partitions within the interface 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 an interface if there is an empty line between them. This helps maintain the defined order of logically separated groups of members.

interface User {
  // Group 1
  firstName: string;
  lastName: string;

  // Group 2
  age: number;
  birthDate: Date;

  // Group 3
  address: string;
  phone?: string;
}

Each group of members (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, and forbid newlines inside groups.

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

See the groups option.

This option is only applicable when partitionByNewLine is false.

[DEPRECATED] groupKind

Use the groups option with the optional and required modifiers instead.

Specifies how optional and required members should be ordered in TypeScript interfaces.

• 'optional-first' — Put all optional members before required members.
• 'required-first' — Put all required members before optional members.
• 'mixed' — Do not enforce any specific order based on optionality.

useConfigurationIf

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

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

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 keys must match.

Example configuration:

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

• declarationMatchesPattern — A regexp pattern that the interface declaration must match.

Example configuration:

{
  'perfectionist/sort-interfaces': [
    'error',
    {
      type: 'unsorted', // Do not sort Metadata interfaces
      useConfigurationIf: {
        declarationMatchesPattern: '*Metadata$',
      },
    },
    {
      type: 'alphabetical' // Fallback configuration
    }
  ],
}

groups

Specifies a list of interface member groups for sorting. Groups help organize members into categories, making your interfaces more readable and maintainable.

Each interface member 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.

interface User {
  firstName: string // unknown
  lastName: string  // unknown
  username: string  // unknown
  job: {            // multiline-member
    // Stuff about job
  }
  localization: {   // multiline-member
    // Stuff about localization
  }
}

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

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

interface Interface {
  // 'index-signature'
  [key: string]: any;
  // 'optional-property'
  description?: string;
  // 'required-method'
  method(): string

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

customGroups

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

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

Defines custom groups to match specific interface members.

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'; sortBy?: 'name' | 'value' }
  sortBy?: 'name' | 'value'
  newlinesInside?: number
  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 interface member 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'; sortBy?: 'name' | 'value' }
  sortBy?: 'name' | 'value'
  newlinesInside?: number
  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 interface member will match a CustomGroupAnyOfDefinition group if it matches all the filters of at least one of the anyOf items.

interface User {
  id: string                 // top
  name: string               // top
  age: number                // unknown
  isAdmin: boolean           // unknown
  lastUpdated_metadata: Date // bottom
  localization?: {            // optional-multiline-member
    // Stuff about localization
  }
  version_metadata: string   // bottom
}

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