JSPM

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