Micro

# micro — Asynchronous HTTP Microservices

You are an expert in micro, Vercel's lightweight framework for building asynchronous HTTP microservices in Node.js. micro makes it easy to write single-purpose HTTP endpoints with minimal boilerplate.

## Installation

```bash
npm install micro
```

## Basic Usage

Create a module that exports a request handler:

```ts
// index.ts
import { serve } from 'micro'

const handler = (req: Request) => {
  return new Response('Hello, World!')
}

serve(handler)
```

Or use the classic API:

```ts
import { IncomingMessage, ServerResponse } from 'http'

export default (req: IncomingMessage, res: ServerResponse) => {
  res.end('Hello, World!')
}
```

Run with:

```bash
npx micro
```

## Core API

### `json(req)` — Parse JSON Body

```ts
import { json } from 'micro'

export default async (req: IncomingMessage, res: ServerResponse) => {
  const body = await json(req)
  return { received: body }
}
```

### `text(req)` — Parse Text Body

```ts
import { text } from 'micro'

export default async (req: IncomingMessage, res: ServerResponse) => {
  const body = await text(req)
  return `You said: ${body}`
}
```

### `buffer(req)` — Parse Raw Body

```ts
import { buffer } from 'micro'

export default async (req: IncomingMessage, res: ServerResponse) => {
  const raw = await buffer(req)
  return `Received ${raw.length} bytes`
}
```

### `send(res, statusCode, data)` — Send Response

```ts
import { send } from 'micro'

export default (req: IncomingMessage, res: ServerResponse) => {
  send(res, 200, { status: 'ok' })
}
```

### `createError(statusCode, message)` — HTTP Errors

```ts
import { createError } from 'micro'

export default (req: IncomingMessage, res: ServerResponse) => {
  if (!req.headers.authorization) {
    throw createError(401, 'Unauthorized')
  }
  return { authorized: true }
}
```

## Development with micro-dev

`micro-dev` provides hot-reloading for development:

```bash
npm install --save-dev micro-dev

# Run in dev mode
npx micro-dev index.js
```

## Composition

Chain multiple handlers with function composition:

```ts
import { IncomingMessage, ServerResponse } from 'http'

const cors = (fn: Function) => async (req: IncomingMessage, res: ServerResponse) => {
  res.setHeader('Access-Control-Allow-Origin', '*')
  return fn(req, res)
}

const handler = async (req: IncomingMessage, res: ServerResponse) => {
  return { hello: