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# no-iterator

[Added in v0.4.2](https://github.com/web-infra-dev/rslint/releases/tag/v0.4.2)
## Configuration


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

export default defineConfig([
  js.configs.recommended,
  {
    rules: {
      'no-iterator': 'error',
    },
  },
]);
```

## Rule Details

Disallow the use of the `__iterator__` property.

The `__iterator__` property was a SpiderMonkey extension to JavaScript that could be used to create custom iterators compatible with `for...in` and `for each...in` loops. However, this property is now obsolete, so it should not be used. The standard `Symbol.iterator` property should be used instead to define the iteration protocol.

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

```javascript
Foo.prototype.__iterator__ = function () {};

var a = test.__iterator__;

var a = test['__iterator__'];
```

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

```javascript
var __iterator__ = null;

var a = test[__iterator__];

Foo.prototype[Symbol.iterator] = function () {};
```

## Original Documentation

- [ESLint: no-iterator](https://eslint.org/docs/latest/rules/no-iterator)
- [Source code](https://github.com/eslint/eslint/blob/v10.8.1/lib/rules/no-iterator.js)