h3

What is h3?

The h3 npm package is a high-performance HTTP framework for Node.js, designed to be lightweight and fast. It is often used for building APIs and microservices, providing a simple and efficient way to handle HTTP requests and responses.

What are h3's main functionalities?

Basic HTTP Server

This code demonstrates how to create a basic HTTP server using the h3 package. The server listens on port 3000 and responds with 'Hello, world!' to any incoming requests.

const { createApp } = require('h3');
const { createServer } = require('http');

const app = createApp();

app.use('/', (req, res) => {
  res.end('Hello, world!');
});

createServer(app).listen(3000, () => {
  console.log('Server is running on http://localhost:3000');
});

Middleware Support

This example shows how to use middleware with the h3 package. The middleware logs each incoming request's method and URL before passing control to the next handler.

const { createApp } = require('h3');
const { createServer } = require('http');

const app = createApp();

// Middleware to log requests
app.use((req, res, next) => {
  console.log(`${req.method} ${req.url}`);
  next();
});

app.use('/', (req, res) => {
  res.end('Hello, world!');
});

createServer(app).listen(3000, () => {
  console.log('Server is running on http://localhost:3000');
});

Routing

This code demonstrates how to set up routing with the h3 package. It defines GET and POST routes for the '/hello' path, responding with different messages based on the HTTP method.

const { createApp, useRouter } = require('h3');
const { createServer } = require('http');

const app = createApp();
const router = useRouter();

router.get('/hello', (req, res) => {
  res.end('Hello, GET!');
});

router.post('/hello', (req, res) => {
  res.end('Hello, POST!');
});

app.use(router);

createServer(app).listen(3000, () => {
  console.log('Server is running on http://localhost:3000');
});

Other packages similar to h3

express

Express is a widely-used web application framework for Node.js, known for its simplicity and flexibility. It provides robust routing, middleware support, and a wide range of HTTP utility methods. Compared to h3, Express is more feature-rich and has a larger community, but it may be heavier and less performant for certain use cases.

koa

Koa is a next-generation web framework for Node.js, created by the same team behind Express. It uses async functions to simplify middleware and improve error handling. Koa is more modular and lightweight compared to Express, similar to h3, but it requires more boilerplate code to set up.

fastify

Fastify is a web framework for Node.js that focuses on performance and low overhead. It provides a schema-based validation system and a powerful plugin architecture. Fastify is similar to h3 in terms of performance and simplicity, but it offers more built-in features and a more extensive plugin ecosystem.

README

What?

• Works perfectly with Serverless, Workers and NodeJS
• Compatible with connect/express middleware
• Tree-shakable and zero-dependency
• Promise and aync/await support
• Lazy loading
• Quick prefix router
• Custom route matcher

See un for workers support

Install

yarn add h3
# or
npm install h3

Usage

Using listhen:

const { createApp } = require('h3')
const { listen } = require('listhen')

const app = createApp()
app.use('/', () => 'Hello world!')

listhen(app)

Using plain node:

const { Server } = require('http')
const { createApp } = require('h3')

const app = createApp()

// Handle can directly return object or Promise<object> for JSON response
app.use('/api', (req) => ({ url: req.url }))

// You can have better matching other than quick prefix match
app.use('/odd', () => 'Is odd!', { match: url => url.substr(1) % 2 })

// Handle can directly return string for HTML response
app.use(() => '<h1>Hello world!</h1>')

// You can chain calls to .use()
app.use('/1', () => '<h1>Hello world!</h1>').use('/2', () => '<h1>Goodbye!</h1>')

// If handle is already async, using useAsync to avoid unnecessary promisify wrapper
// (Shortcut to pass { promisify: false })
// app.useAsync(async () => {})

// Lazy loading routes using { lazy: true }
// app.use('/big', () => import('./big'), { lazy: true })

const port = process.env.PORT || 3000
const server = new Server(app)

server.listen(port, () => {
  console.log(`Listening on: http://localhost:${port}`)
})

Technical

There are two vital parts that make it working: Stack Runner (App), and promisifyHandle.

App

App is basically a http server handle with req, res and attached utilities that runs a stack of middleware/handles in parallel. It will stop when the writableEnded flag is set on a response (which means that res.end has been called) and throw a 404 if writableEnded flag has not been set by the end.

Additionally the app has a quick prefix matcher and will automatically call res.end if any stack layers return a value.

promisifyHandle

Converts a classic middleware (req, res, next?) into a promisified version ready to use with App

• If middleware has 3rd next/callback param, promise will resolve/reject when called
• If middleware returns a promise, it will be chained to main promise
• If calling middleware throws an immediate error, promise will be rejected
• On close and error events of res, promise will resolve/reject (to ensure if middleware simply calls res.end)

When calling app.use, middleware will be automatically promisified.

If you are already making an async aware middleware, you can use app.useAsync

License

MIT