Application

設定 (Settings)

app.env defaulting to the NODE_ENV or "development"

❗app.listen(...)

A Koa application is not a 1-to-1 representation of an HTTP server. One or more Koa applications may be mounted together to form larger applications with a single HTTP server.

const http = require('http')
const https = require('https')
const Koa = require('koa')
const app = new Koa()
http.createServer(app.callback()).listen(3000)
https.createServer(app.callback()).listen(3001)

app.callback()

Return a callback function suitable for the http.createServer() method to handle a request. You may also use this callback function to mount your Koa app in a Connect/Express app.

❗app.use(function)

Add the given middleware function to this application. See Middleware for more information.

❗app.context

app.context.db = db()

app.use(async (ctx) => {
  console.log(ctx.db)
})

錯誤處理 (Error Handling)

app.on('error', (err) => {
  log.error('server error', err)
})