# sort-switch-case

Enforce sorted switch case statements.

Switch statements with numerous cases can quickly become cumbersome and hard to navigate. With this rule, you can easily locate specific cases and ensure that your codebase adheres to a predictable and standardized format.

This practice contributes to a more readable and maintainable codebase, allowing developers to quickly understand and modify the logic without getting lost in a jumble of unsorted case clauses.

By integrating this rule into your ESLint configuration, you can focus on the functionality of your code, confident that your switch statements are consistently structured and easy to manage.

## Try it out

**Initial**

```tsx
const userReducer = (state = initialState, action) => {
  switch (action.type) {
    case 'FETCH_USER_ERROR':
      return {
        ...state,
        loading: false,
        error: action.payload,
      }
    case 'FETCH_USER_SUCCESS':
      return {
        ...state,
        loading: false,
        currentUser: action.payload,
      }
    case 'DELETE_USER':
      return {
        ...state,
        users: state.users.filter(user => user.id !== action.payload.id),
      }
    case 'FETCH_USER_REQUEST':
      return {
        ...state,
        loading: true,
        error: null,
      }
    case 'ADD_USER':
      return {
        ...state,
        users: [...state.users, action.payload],
      }
    default:
      return state
  }
}
```

**Sorted alphabetically**

```tsx
const userReducer = (state = initialState, action) => {
  switch (action.type) {
    case 'ADD_USER':
      return {
        ...state,
        users: [...state.users, action.payload],
      }
    case 'DELETE_USER':
      return {
        ...state,
        users: state.users.filter(user => user.id !== action.payload.id),
      }
    case 'FETCH_USER_ERROR':
      return {
        ...state,
        loading: false,
        error: action.payload,
      }
    case 'FETCH_USER_REQUEST':
      return {
        ...state,
        loading: true,
        error: null,
      }
    case 'FETCH_USER_SUCCESS':
      return {
        ...state,
        loading: false,
        currentUser: action.payload,
      }
    default:
      return state
  }
}
```

**Sorted by line length**

```tsx
const userReducer = (state = initialState, action) => {
  switch (action.type) {
    case 'FETCH_USER_REQUEST':
      return {
        ...state,
        loading: true,
        error: null,
      }
    case 'FETCH_USER_SUCCESS':
      return {
        ...state,
        loading: false,
        currentUser: action.payload,
      }
    case 'FETCH_USER_ERROR':
      return {
        ...state,
        loading: false,
        error: action.payload,
      }
    case 'DELETE_USER':
      return {
        ...state,
        users: state.users.filter(user => user.id !== action.payload.id),
      }
    case 'ADD_USER':
      return {
        ...state,
        users: [...state.users, action.payload],
      }
    default:
      return state
  }
}
```

## 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](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/localeCompare).
- `'natural'` — Sort items in a [natural](https://github.com/yobacca/natural-orderby) 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`](#alphabet) option.
- `'unsorted'` — Do not sort items.

### 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' | 'unsorted'
  order?: 'asc' | 'desc'
}
```

default: `{ type: 'unsorted' }`

Specifies fallback sort options for elements that are equal according to the primary sort [`type`](#type).

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

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

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

### alphabet

default: `''`

Used only when the [`type`](#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](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/localeCompare#locales).

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

## Usage

**Flat Config**

```tsx
// eslint.config.js
import perfectionist from 'eslint-plugin-perfectionist'

export default [
  {
    plugins: {
      perfectionist,
    },
    rules: {
      'perfectionist/sort-switch-case': [
        'error',
        {
          type: 'alphabetical',
          order: 'asc',
          fallbackSort: { type: 'unsorted' },
          ignoreCase: true,
          specialCharacters: 'keep',
        },
      ],
    },
  },
]
```

**Legacy Config**

```tsx
// .eslintrc.js
module.exports = {
  plugins: [
    'perfectionist',
  ],
  rules: {
    'perfectionist/sort-switch-case': [
      'error',
      {
        type: 'alphabetical',
        order: 'asc',
        fallbackSort: { type: 'unsorted' },
        ignoreCase: true,
        specialCharacters: 'keep',
      },
    ],
  },
}
```

## Version

This rule was introduced in [v3.0.0](https://github.com/azat-io/eslint-plugin-perfectionist/releases/tag/v3.0.0).

## Resources

- [Rule source](https://github.com/azat-io/eslint-plugin-perfectionist/blob/main/rules/sort-switch-case.ts)
- [Test source](https://github.com/azat-io/eslint-plugin-perfectionist/blob/main/test/rules/sort-switch-case.test.ts)