example.js

const logger = require('./')
const Koa = require('koa')
const compress = require('koa-compress')()
const app = new Koa()

// wrap subsequent middleware in a logger

app.use(logger())

// 204

app.use(function (ctx, next) {
  if (ctx.path === '/204') ctx.status = 204
  else return next()
})

// 404

app.use(function (ctx, next) {
  if (ctx.path === '/404') return
  return next()
})

// destroy

app.use(function (ctx, next) {
  if (ctx.path === '/close') return ctx.req.destroy()
  return next()
})

// compress the response 1/2 the time to calculate the stream length

app.use(function (ctx, next) {
  if (Math.random() > 0.5) {
    return next()
  } else {
    return compress(ctx, next)
  }
})

// response middleware

app.use(function (ctx, next) {
  // yield control downstream
  next().then(function () {
    // sleep for 0-2s
    return sleep(Math.random() * 2000 | 0)
  }).then(function () {
    // error
    if (Math.random() > 0.75) {
      const err = new Error('boom')
      err.status = 500
      throw err
    }

    // random body
    const body = Array(Math.random() * 5 * 1024 | 9).join('a')
    ctx.status = 200
    ctx.body = body
  })
})

const port = process.env.PORT || 3000
app.listen(port)
console.log('listening on port ' + port)

// sleep helper

function sleep (ms) {
  return new Promise(function (resolve) {
    setTimeout(resolve, ms)
  })
}