> For AI agents: the complete documentation index is available at https://rslint.rs/llms.txt, the full documentation bundle is available at https://rslint.rs/llms-full.txt.

# js

`js` exposes presets for Rslint's built-in implementation of supported [ESLint 10.x core rules](https://eslint.org/docs/v10.x/rules/). Its preset is based on the configuration published by `@eslint/js` 10.x.

```ts
import { defineConfig, js } from '@rslint/core';

export default defineConfig([js.configs.recommended]);
```

## Presets

| Preset                   | Description                  | View rules                                                                     | Source                                                                                                                             |
| ------------------------ | ---------------------------- | ------------------------------------------------------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------- |
| `js.configs.recommended` | JavaScript recommended rules | [View rules →](https://rslint.rs/rules/index.md?preset=js.configs.recommended) | [`@eslint/js` `configs.recommended`](https://eslint.org/docs/v10.x/use/configure/migration-guide#predefined-and-shareable-configs) |

See [Rules & Presets](https://rslint.rs/config/rules-and-presets.md) for guidance on choosing and layering presets.

## Differences from ESLint

Unlike the upstream preset, `js.configs.recommended` intentionally omits `no-undef`.

The rule is only accurate when all globals provided by browsers, Node.js, and other environments are declared in the configuration. Because a general-purpose preset cannot know which environments apply to each file, enabling the rule by default would report valid global references until users add the corresponding environment-specific configuration.

To enable this check, declare the globals available to matching files first:

```ts
import { defineConfig, globals, js } from '@rslint/core';

export default defineConfig([
  js.configs.recommended,
  {
    files: ['src/**/*.{js,jsx}'],
    languageOptions: {
      globals: {
        ...globals.browser,
      },
    },
    rules: {
      'no-undef': 'error',
    },
  },
]);
```