---
title: Usage
---

## Installation

```package-install
npm i -D @monstermann/stdlib-transform
```

## Setup

### Vite, Rolldown, tsdown

**Vite**

```ts vite.config.ts
import { stdlib } from "@monstermann/stdlib-transform"
import { defineConfig } from "vite"

export default defineConfig({
    plugins: [stdlib()],
})
```

**Rolldown**

```ts rolldown.config.ts
import { stdlib } from "@monstermann/stdlib-transform"
import { defineConfig } from "rolldown"

export default defineConfig({
    input: "src/index.ts",
    plugins: [stdlib()],
})
```

**tsdown**

```ts tsdown.config.ts
import { stdlib } from "@monstermann/stdlib-transform"
import { defineConfig } from "tsdown"

export default defineConfig({
    entry: "src/index.ts",
    plugins: [stdlib()],
})
```

### Bun

For `Bun.build`:

```ts build.ts
import { stdlibBun } from "@monstermann/stdlib-transform"

await Bun.build({
    entrypoints: ["./src/index.ts"],
    plugins: [stdlibBun()],
})
```

For `bun run` and `bun test`, register it in a preload:

```ts preload.ts
import { stdlibBun } from "@monstermann/stdlib-transform"
import { plugin } from "bun"

plugin(stdlibBun())
```

```toml bunfig.toml
preload = ["./preload.ts"]

[test]
preload = ["./preload.ts"]
```

Bun only uses the first plugin that returns something for a file. With other plugins, call `transform(code, path)` from your own instead.

## Options

| Option    | Default                   | Description                                                  |
| --------- | ------------------------- | ------------------------------------------------------------ |
| `include` | `/\.m?[jt]sx?(?:\?.*)?$/` | Only files whose path matches one of these are transformed.  |
| `exclude` |                           | Files whose path matches one of these are skipped.           |
| `debug`   | `false`                   | `true`, or a RegExp of paths: prints what is being replaced. |
| `enforce` |                           | `"pre"` or `"post"`, not for Bun.                            |

Dependencies in `node_modules` are never transformed.