Koa starter

The code

Two files, exactly what you get in the editor.

import Koa from 'koa'

const app = new Koa()

// Middleware runs downstream, then back upstream.
app.use(async (ctx, next) => {
  const start = performance.now()
  await next()
  const ms = (performance.now() - start).toFixed(1)
  ctx.set('X-Response-Time', `${ms}ms`)
  console.log(`${ctx.method} ${ctx.url} ${ctx.status} ${ms}ms`)
})

app.use(async (ctx) => {
  if (ctx.path === '/api/echo') {
    ctx.body = { method: ctx.method, query: ctx.query, headers: ctx.headers }
    return
  }
  ctx.type = 'html'
  ctx.body = '<h1>Hello from Koa</h1><p>See <a href="/api/echo?hi=there">/api/echo</a>.</p>'
})

const port = Number(process.env.PORT) || 3000
app.listen(port, () => console.log(`Koa on port ${port}`))

{
  "name": "koa-server",
  "private": true,
  "type": "module",
  "dependencies": {
    "koa": "^3.0.0"
  }
}