我正在尝试将以下ES6脚本转换为带扣脚本，但我终生无法弄清楚如何在带扣脚本中创建“关闭”

    import {Socket,Presence} from "phoenix"

    let socket = new Socket("/socket",{
      params: {user_id: window.location.search.split("=")[1]}
    })

    let channel = socket.channel("room:lobby",{})
    let presence = new Presence(channel)

    function renderOnlineUsers(presence) {
      let response = ""

      presence.list((id,{metas: [first,...rest]}) => {
        let count = rest.length + 1
        response += `<br>${id} (count: ${count})</br>`
      })

      document.querySelector("main[role=main]").innerHTML = response
    }

    socket.connect()

    presence.onSync(() => renderOnlineUsers(presence))

    channel.join()

我无法明确指出的部分是let response = ""（或var，在这种情况下，因为扣脚本始终使用var s）

    function renderOnlineUsers(presence) {
      let response = ""

      presence.list((id,...rest]}) => {
        let count = rest.length + 1
        response += `<br>${id} (count: ${count})</br>`
      })

      document.querySelector("main[role=main]").innerHTML = response
    }

到目前为止，我获得的最接近值不包括result声明

...
...

let onPresenceSync ev =
  let result = "" in
    let listFunc = [%raw begin
        {|
          (id,...rest]}) => {
            let count = rest.length + 1
            result += `${id} (count: ${count})\n`
          }
        |}
      end
    ] in
      let _ =
        presence |. listPresence (listFunc) in
          [%raw {| console.log(result) |} ]
...
...

编译为：

function onPresenceSync(ev) {
  var listFunc = (
          (id,...rest]}) => {
            let count = rest.length + 1
            result += `${id} (count: ${count})\n`
          }
        );
  presence.list(listFunc);
  return ( console.log(result) );
}