prerender-spa-plugin未渲染出meta信息

Question

//webpack.prod.conf.js
const PrerenderSpaPlugin = require('prerender-spa-plugin')
const Renderer = PrerenderSpaPlugin.PuppeteerRenderer

const webpackConfig = merge(baseWebpackConfig, {
    // ...
    plugins: [
    // ...
        new PrerenderSpaPlugin({
        staticDir: path.join(__dirname, '../dist'),
        routes: ['/index'],
        renderer: new Renderer({
          renderAfterTime: 5000
        })
      })
    ]
})

//config/index.js
  build: {
    // Template for index.html
    index: path.resolve(__dirname, '../dist/index.html'),

    // Paths
    assetsRoot: path.resolve(__dirname, '../dist'),
    assetsSubDirectory: 'static',
    assetsPublicPath: '/promotion/'
    }

// main.js

new Vue({
  el: '#app',
  router,
  render: h => h(App),
  mounted () {
    document.dispatchEvent(new Event('render-event'))
  }
})

我的服务器已经支持history模式，可以正常访问，
现在想要将index也做成预渲染，
可是按照如上配置打包后，虽然生成了单独的index文件夹和index.html文件，
但依然没有设置的一些meta信息，这怎么破？