在vue-ssr项目中渲染一个vue实例，直接像spa那样初始化vue实例的话事件不会被触发，想知道怎么给template中的dom元素绑定事件？

相关代码

const fs = require('fs')
const Vue = require('vue')
const server = require('express')()
const VueServerRenderer = require('vue-server-renderer')
const renderer = VueServerRenderer.createRenderer({
  template: fs.readFileSync('./index.template.html', 'utf-8')
})

server.get('*', (req, res) => {
  const app = new Vue({
    template: `
      <div>
        <button @click="testFun">click me</button>
        <br/>
      </div>
    `,
    methods: {
      testFun() {
        console.log('----------------')
      }
    }
  })

  renderer.renderToString(app, context).then(html => {
    res.end(`${html}`)
  }).catch(err => {
    res.status(500).end('Internal Server Error')
    return
  })
})

server.set('port', process.env.PORT || 6666)
let hostname = '127.0.0.1'
server.listen(server.get('port'), hostname, () => {
  console.log(`Server running at http://${hostname}:${server.get('port')}`)
})

希望知道怎么在ssr中写这些函数，谢谢