---
title: Configuration
---

**@roots/bud-swc** works with zero configuration. But there is a robust and developer friendly configuration API should you need to make a modification to the provided defaults.

## Configuration with .swcrc

Including a `.swcrc` config file in the root of your project will replace all default options.

This is not recommended if you want to use other extensions which manipulate swc options (like **@roots/bud-react** and **@roots/bud-emotion**).

## Configuration with `bud.swc`

You can configure `jsc` with the `bud.swc.setJsc` method:

```ts title=bud.config.ts
bud.swc.setJsc({
  baseUrl: `/base/url/`,
})
```

```ts title=bud.config.ts
bud.swc.setJsc((jsc = {}) => ({
  ...jsc,
  baseUrl: `/base/url/`,
}))
```

Many `jsc` options have associated helper methods which don't require using `bud.swc.setJsc` directly. These should be preferred over `bud.swc.setJsc` whenenver possible.

### jsc.baseUrl

Use the `bud.swc.setBaseUrl` method to configure `jsc.baseUrl`

```ts title=bud.config.ts
bud.swc.setBaseUrl(`/base/url/`)
```

### jsc.externalHelpers

Use the `bud.swc.setExternalHelpers` method to configure `jsc.externalHelpers`

```ts title=bud.config.ts
bud.swc.setExternalHelpers(true)
```

### jsc.experimental

Use the `bud.swc.setExperimental` method to configure `jsc.experimental`

```ts title=bud.config.ts
bud.swc.setExperimental({plugins: []})
```

If you want to set `jsc.experimental.plugins` you may wish to use the [`bud.swc.setPlugins` method](#plugins).

### jsc.loose

Use the `bud.swc.setLoose` method to configure `jsc.loose`

```ts title=bud.config.ts
bud.swc.setLoose(true)
```

### jsc.minify

Use the `bud.swc.setMinify` method to configure `jsc.minify`

```ts title=bud.config.ts
bud.swc.setMinify(true)
```

### jsc.parser

To configure the parser you can use [bud.swc.setParser].

Example:

```ts title=bud.config.ts
bud.swc.setParser({decorators: false})
```

Note that `jsx.parser.syntax`, `jsc.parser.jsx` and `jsc.parser.tsx` will be overwritten by [syntax specific configuration](#syntax-specific-jsc-configuration). You should change those options using `bud.swc.ecmascript.setParser` or `bud.swc.typescript.setParser` instead of using the base options.

### jsc.preserveAllComments

Use the `bud.swc.preserveAllComments` method to oconfigure `jsc.preserveAllComments`

```ts title=bud.config.ts
bud.swc.preserveAllComments(false)
```

### jsc.target

Use the `bud.swc.setTarget` method to configure `jsc.target`

```ts title=bud.config.ts
bud.swc.setTarget(`es5`)
```

### jsc.transform

Use the `bud.swc.setTransform` method to configure `jsc.transform`

```ts title=bud.config.ts
bud.swc.setTransform({})
```

## Syntax specific jsc configuration

SWC supports both `ecmascript` and `TypeScript`. If you want to make changes to the `jsc` config which are only applied to a specific syntax, you can make overrides using `bud.swc.ecmascript` and `bud.swc.typescript`, respectively.

```ts title=bud.config.ts
bud.swc.ecmascript.setKeepClassNames(true)
bud.swc.typescript.setKeepClassNames(false)
```

All of the above `jsc.*` options work the same way as detailed above.

## Plugins

Use the `bud.swc.setPlugins` method to configure `experimental.plugins`:

```ts title=bud.config.ts
bud.swc.setPlugins([['some-swc-plugin', {}]])
```

```ts title=bud.config.ts
bud.swc.setPlugins((plugins = []) => [...plugins, ['some-swc-plugin', {}]])
```

## Env

Use the `bud.swc.setEnv` method to configure swc `env` options:

```ts title=bud.config.ts
bud.swc.setEnv({
  targets: `Chrome >= 48`,
})
```

## Source maps

Use the `bud.swc.setSourceMaps` method to configure the swc `sourceMaps` option:

```ts title=bud.config.ts
bud.swc.setSourceMaps(`inline`)
```