npm install --save koa-bodyparser

 const Koa = require('koa')

 const bodyParser = require('koa-bodyparser')

 const app = new Koa()

 app.use(bodyParser())

 app.use(async ctx => {

   if (ctx.url === '/' && ctx.method === 'GET') {

     const html = `

       <h1>koa2 request post demo</h1>

       <form method="POST" action="/">

         <p>userName</p>

         <input name="userName" /><br/>

         <p>nickName</p>

         <input name="nickName" /><br/>

         <p>email</p>

         <input name="email" /><br/>

         <button type="submit">submit</button>

       </form>

     `

     ctx.body = html

   } else if (ctx.url === '/' && ctx.method === 'POST') {

     const postData = ctx.request.body

     ctx.body = postData

   } else {

     ctx.body = `<h1>404!!!</h1>`

   }

 })

 app.listen(4000, () => {

   console.log('[demo] request post is starting at port 4000')

 })

node demo.js