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

# Rslib

[Rslib](https://rslib.rs) is a library development tool built on Rsbuild for creating JavaScript libraries and UI component libraries.

If your library uses Rslib, you can use Rstest to test it and reuse the test-relevant parts of your Rslib configuration through an adapter. This reduces duplicate configuration and helps keep test compilation consistent with your library build.

## Quick start

### New project

Create a new Rslib + Rstest project with the `--tools rstest` flag:

```bash
npx create-rslib --template react-ts --tools rstest --dir my-project
```

The scaffold includes Rstest and demo tests. Run them with `npm run test`.

### Existing project

To add Rstest to an existing project, follow the [Quick Start](/guide/start/quick-start.md) to install and set up test scripts.

## Reuse Rslib config

[@rstest/adapter-rslib](https://www.npmjs.com/package/@rstest/adapter-rslib) loads your Rslib config and converts the test-relevant parts into Rstest configuration.

### Install adapter


```sh [npm]
npm add @rstest/adapter-rslib -D
```

```sh [yarn]
yarn add @rstest/adapter-rslib -D
```

```sh [pnpm]
pnpm add @rstest/adapter-rslib -D
```

```sh [bun]
bun add @rstest/adapter-rslib -D
```

```sh [deno]
deno add npm:@rstest/adapter-rslib -D
```

### Extend your config

```ts title="rstest.config.ts"
import { defineConfig } from '@rstest/core';
import { withRslibConfig } from '@rstest/adapter-rslib';

export default defineConfig({
  extends: withRslibConfig(),
});
```

The adapter loads `rslib.config.ts`, maps options used by test compilation, merges them with your Rstest config, and adds the loaded config file to [`forceRerunTriggers`](/config/test/force-rerun-triggers.md), so `--changed` runs the full test suite when that config changes.

It does not copy build-only settings such as `dev`, `server`, or `html`. Use `cwd`, `config`, or `libId` when the default config location or library selection does not match your project.

For all options, configuration mapping, cache behavior, and debug instructions, see the [configuration reference](/integration/rslib/reference.md).

## Related documentation

- [Rslib configuration overview](https://rslib.rs/config)