sort-type-constituents.md

description
Enforce constituents of a type union/intersection to be sorted alphabetically.

🛑 This file is source code, not the primary documentation location! 🛑

See https://typescript-eslint.io/rules/sort-type-constituents for documentation.

Sorting union (|) and intersection (&) types can help:

• keep your codebase standardized
• find repeated types
• reduce diff churn

This rule reports on any types that aren't sorted alphabetically.

Types are sorted case-insensitively and treating numbers like a human would, falling back to character code sorting in case of ties.

Examples

❌ Incorrect

type T1 = B | A;

type T2 = { b: string } & { a: string };

type T3 = [1, 2, 4] & [1, 2, 3];

type T4 =
  | [1, 2, 4]
  | [1, 2, 3]
  | { b: string }
  | { a: string }
  | (() => void)
  | (() => string)
  | 'b'
  | 'a'
  | 'b'
  | 'a'
  | readonly string[]
  | readonly number[]
  | string[]
  | number[]
  | B
  | A
  | string
  | any;

✅ Correct

type T1 = A | B;

type T2 = { a: string } & { b: string };

type T3 = [1, 2, 3] & [1, 2, 4];

type T4 =
  | any
  | string
  | A
  | B
  | number[]
  | string[]
  | readonly number[]
  | readonly string[]
  | 'a'
  | 'b'
  | 'a'
  | 'b'
  | (() => string)
  | (() => void)
  | { a: string }
  | { b: string }
  | [1, 2, 3]
  | [1, 2, 4];

Options

groupOrder

Each constituent of the type is placed into a group, and then the rule sorts alphabetically within each group. The ordering of groups is determined by this option.

• conditional - Conditional types (A extends B ? C : D)
• function - Function and constructor types (() => void, new () => type)
• import - Import types (import('path'))
• intersection - Intersection types (A & B)
• keyword - Keyword types (any, string, etc)
• literal - Literal types (1, 'b', true, etc)
• named - Named types (A, A['prop'], B[], Array<C>)
• object - Object types ({ a: string }, { [key: string]: number })
• operator - Operator types (keyof A, typeof B, readonly C[])
• tuple - Tuple types ([A, B, C])
• union - Union types (A | B)
• nullish - null and undefined