# filenames-simple/named-export

This rule checks the export name is same as filename.

**NOTE:** this rule is only enabled when `parserOptions.ecmaVersion` in `.eslintrc` is set to `6` (`2015`) or later.

## Configuration example

```json
{
  "plugins": ["filenames-simple"],
  "rules": {
    "filenames-simple/named-export": ["error", "singular"]
  }
}
```

## Available options

### rule: (the first option)

Specify one of the following as the file naming convention to which this rule applies.

#### Naming convention presets

- always (default): Always check the export name.
- singular: Check the export name only if filename is singular.
- plural: Check the export name only if filename is plural.

## Rule details

### Basic

- module.js
  ```javascript
  // OK
  export const module = 1;
  ```
- module.js

  ```javascript
  // NG: You can use `mod.js` or `Mod.js` as filename.
  export const mod = 1;
  ```

- module.js
  ```javascript
  // default export is ignored
  const module = 1;
  export default module;
  ```
- modules.js
  ```javascript
  // Multiple named exports are ignored too.
  const module1 = 1;
  const module2 = 2;
  export { module1, module2 };
  ```
- module.js
  ```javascript
  // It is ignored when the file includes both default export and named export.
  const module = 1;
  export default module;
  export const extraModule = { key: 'value' };
  ```

### When the name of exported module contains two or more words

- my-class.js
  ```javascript
  /*
   * When the name of exported module is written in camelCase or PascalCase,
   * the filename can be written in `kebab-case`, `camelCase` or `PascalCase`
   */
  export class MyClass {}
  ```
- myFunction.js
  ```javascript
  // `my-function.js`, `MyFunction.js` is also OK.
  export function myFunction() {}
  ```

### When the filename is `index.js` (`index.ts`)

- src/rules/index.js
  ```javascript
  // The rule checks the parent directory name with the name of exported module.
  export const rules = {};
  ```
- src/config/index.js
  ```javascript
  // Multiple named export are ignored.
  export { all } from './all';
  export { recommended } from './recommended';
  ```

### You can also lint TypeScript notations

- fruits.ts
  ```typescript
  export enum fruits {
    orange = 'orange',
    apple = 'apple',
    banana = 'banana',
  }
  ```
- identifier.ts
  ```typescript
  export interface Identifier {
    name: string;
  }
  ```
- class-expression.d.ts
  ```typescript
  export type ClassExpression = { id: Identifier };
  ```

#### NOTE: This rule skips the detection of named exports in TypeScript module blocks.

- @types/espree.d.ts
  ```typescript
  declare module 'espree' {
    export function parse(code: string, options?: any): Node;
  }
  ```

## See also

- [settings/pluralize](../settings/pluralize.md)