LiveBeats: Building a social music app with Phoenix LiveView(fly.io)

    //js
    Hooks.Ping = {
      mounted(){
        this.handleEvent("pong", () => {
          let rtt = Date.now() - this.nowMs
          this.el.innerText = `ping: ${rtt}ms`
          this.timer = setTimeout(() => this.ping(rtt), 1000)
        })
        this.ping(null)
      },
      destroyed(){ clearTimeout(this.timer) },
      ping(rtt){
        this.nowMs = Date.now()
        this.pushEvent("ping", {rtt: rtt})
      }
    }

    //liveview
    defp handle_event("ping", %{"rtt" => rtt}, socket) do
      {:halt,
       socket
       |> rate_limited_ping_broadcast(socket.assigns.current_user, rtt)
       |> push_event("pong", %{})}
    end