const Koa = require('koa')
const app = new Koa()

app.use( async ( ctx ) => {

  if ( ctx.url === '/index' ) {
    ctx.cookies.set(
      'cid', 
      'hello world',
      {
        domain: 'localhost',  // 写cookie所在的域名
        path: '/index',       // 写cookie所在的路径
        maxAge: 10 * 60 * 1000, // cookie有效时长
        expires: new Date('2017-02-15'),  // cookie失效时间
        httpOnly: false,  // 是否只用于http请求中获取
        overwrite: false  // 是否允许重写
      }
    )
    ctx.body = 'cookie is ok'
  } else {
    ctx.body = 'hello world' 
  }

})

app.listen(3000, () => {
  console.log('[demo] cookie is starting at port 3000')
})

node index.js