text: const {
    SocketIOConnection
  } = require('@livingspec/slate-collaborative-backend')
  const express = require('express')
  
  const defaultValue = [
    {
      type: 'paragraph',
      children: [
        {
          text: 'Hello collaborator!'
        }
      ]
    }
  ]
  
  const PORT = process.env.PORT || 9000
  
  const server = express()
    .use(express.static('build'))
    .listen(PORT, () => console.log(`Listening on ${PORT}`))
  
  const config = {
    entry: server, // or specify port to start io server
    defaultValue,
    saveFrequency: 2000,
    onAuthRequest: async (query, socket) => {
      // some query validation
      return true
    },
    onDocumentLoad: async pathname => {
      // request initial document ValueJSON by pathnme
      return defaultValue
    },
    onDocumentSave: async (pathname, doc) => {
      // save document
      // console.log('onDocumentSave', pathname, doc)
    }
  }
  
  const connection = new SocketIOConnection(config)
  