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# require-array-join-separator

[Added in v0.7.0](https://github.com/web-infra-dev/rslint/releases/tag/v0.7.0)
## Configuration

| Preset                              | Configured Value |
| ----------------------------------- | ---------------- |
| ✅ unicornPlugin.configs.recommended | `"error"`        |


```ts title=rslint.config.ts
import { defineConfig, unicornPlugin } from '@rslint/core';

export default defineConfig([
  unicornPlugin.configs.recommended,
  {
    rules: {
      'unicorn/require-array-join-separator': 'error',
    },
  },
]);
```

## Rule Details

Enforces passing an explicit separator to `Array#join()` instead of relying on
the default comma separator.

Examples of **incorrect** code for this rule:

```javascript
const string = array.join();
const arrayLikeString = Array.prototype.join.call(arrayLike);
```

Examples of **correct** code for this rule:

```javascript
const string = array.join(',');
const arrayLikeString = Array.prototype.join.call(arrayLike, '');
```

## Original Documentation

- [eslint-plugin-unicorn: require-array-join-separator](https://github.com/sindresorhus/eslint-plugin-unicorn/blob/v64.0.0/docs/rules/require-array-join-separator.md)
- [Source code](https://github.com/sindresorhus/eslint-plugin-unicorn/blob/v64.0.0/rules/require-array-join-separator.js)