README example failes in JupyterLab

[ricochet1k]

I'm trying to use JupyterLab over an SSH tunnel, forwarding ports 8888 and 8081 to the host where I have jupyter and Julia installed. When I copy and paste the example from your README.md, I get this:

┌ Error: error handling request
│   exception = (MethodError(var"#3#5"(), (Session(Base.RefValue{Bool}(false), WebSockets.WebSocket[], Dict{String,Tuple{Bool,Observable}}(), Dict{Symbol,Any}[], Set(JSServe.Asset[]), JSServe.JSCode[], "f71ccc17-116c-4c93-b9ba-42a7ca2bf735", JSServe.init_session), HTTP.Messages.Request:
"""
GET /show HTTP/1.1
Host: 127.0.0.1:8081
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:73.0) Gecko/20100101 Firefox/73.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Connection: keep-alive
Referer: http://localhost:8888/lab?
Upgrade-Insecure-Requests: 1

"""), 0x00000000000068d9), Base.StackTraces.StackFrame[#invokelatest#1 at essentials.jl:709 [inlined], invokelatest at essentials.jl:708 [inlined], serve_dom(::NamedTuple{(:routes, :application, :request, :match),Tuple{JSServe.Routes,Application,HTTP.Messages.Request,String}}, ::Function) at types.jl:263, (::JSServe.var"#59#60"{JSServe.DisplayInline})(::NamedTuple{(:routes, :application, :request, :match),Tuple{JSServe.Routes,Application,HTTP.Messages.Request,String}}) at display.jl:44, apply_handler(::Function, ::NamedTuple{(:routes, :application, :request, :match),Tuple{JSServe.Routes,Application,HTTP.Messages.Request,String}}) at types.jl:105, delegate(::JSServe.Routes, ::Application, ::HTTP.Messages.Request) at types.jl:124, #8 at types.jl:247 [inlined], handle at Handlers.jl:253 [inlined], handle(::HTTP.Handlers.RequestHandlerFunction{JSServe.var"#8#10"{Application}}, ::HTTP.Streams.Stream{HTTP.Messages.Request,HTTP.ConnectionPool.Transaction{Sockets.TCPSocket}}) at Handlers.jl:276, stream_handler(::Application, ::HTTP.Streams.Stream{HTTP.Messages.Request,HTTP.ConnectionPool.Transaction{Sockets.TCPSocket}}) at types.jl:251, #invokelatest#1 at essentials.jl:709 [inlined], invokelatest at essentials.jl:708 [inlined], #21 at types.jl:344 [inlined], macro expansion at Servers.jl:360 [inlined], (::HTTP.Servers.var"#13#14"{JSServe.var"#21#23"{Application},HTTP.ConnectionPool.Transaction{Sockets.TCPSocket},HTTP.Streams.Stream{HTTP.Messages.Request,HTTP.ConnectionPool.Transaction{Sockets.TCPSocket}}})() at task.jl:333])
└ @ HTTP.Servers /home/matt/.julia/packages/HTTP/lZVI1/src/Servers.jl:364

I got to this by trying to display some very simple plots with Makie using the WGLMakie backend. When I try that, I get this:

┌ Error: Error in Javascript: Could not find heap object: 1517845540909878286
│  with exception:
└ @ JSServe /home/matt/.julia/packages/JSServe/4bedp/src/http.jl:154

My apologies if this isn't the right place to report the bug, I'm new to Julia. I'm using Firefox here, if that makes any difference.

[terasakisatoshi]

Maybe, this issue can be closed. JSServe runs on JupyterLab v3

$ jupyter lab --version
3.0.6