Write (python) dash vs Dash.jl feature comparison table

[etpinard]

and put it in the Dash.jl README.md somewhere?

Resources:

• python dash changelog: https://github.com/plotly/dash/blob/dev/CHANGELOG.md
• Dash.jl assets: https://github.com/plotly/DashCoreResources

[etpinard]

Tentative list

Things that are missing from Dash.jl since before Dash.jl v1 (and dash v1.15.0)

taken from the TODO items in https://github.com/plotly/Dash.jl/projects/1

• User-defined routes Support for user-defined routes #35
• Debug logging Logging capability for debugging purposes #13

Things that are missing from Dash.jl from dash v1.x

• from dash v1.16.0, app.csp_hashes()
• from dash v1.19.0 input-output callbacks
• from dash v1.20.0 app(; extra_hot_reload_paths=#= =#)

Things that are missing from Dash.jl since dash v2

note the dash v2 was released on 2021-08-03 🙃

• background (fka long) callbacks
• native pages
• make app(; compress=false) by default
• options / value positional arguments for dash core components https://dash.plotly.com/flexible-callback-signatures
• components as arguments for Input, State and Output
• helpers get_relative_path, strip_relative_path, get_asset_url
• improved callback context
• dash Patch
• allow_duplicate to Output arguments
• dash(; include_pages_meta=true)

Things that are missing from Dash.jl since dash v3

released in march 2025

• dash hooks

Things that maybe just work using resources from dash >= v2.10.2

Dash.jl resources were updated in #212 after an 18+ month hiatus. The update resources are set to be released as part of the upcoming Dash.jl v1.3.0.

TODO, check if

• dcc_geolocation
• Promise in clientside callbacks
• Mathjax in dcc_markdown and dcc_graph
• Component as props - update: does not work, more info below ❌
• dcc_dropdown search prop and maxHeight
• new prop disable_n_clicks
• dcc_location refresh="callback-nav" - update: does not work, more info below ❌

work in Dash.jl.

[etpinard]

Update

dcc_geolocation just works ✔️ 🎉 🍾

Tested with https://dash.plotly.com/dash-core-components/geolocation translated in Julia as:

see Julia snippet

using Dash

app = dash()

app.layout = html_div() do
    html_button("Update Position"; id = "update_btn"),
    dcc_geolocation(; id = "geolocation"),
    html_div(; id="text_position")
end

callback!(app,
          Output("geolocation", "update_now"),
          Input("update_btn", "n_clicks")) do click
    return !isnothing(click) && (click > 1)
end

callback!(app,
          Output("text_position", "children"),
          Input("geolocation", "local_date"),
          Input("geolocation", "position")) do date, pos
    isnothing(pos) && return "No position data available"
    return html_p("As of $date your location was:
                  lat $(pos.lat), lon $(pos.lon), accuracy $(pos.accuracy) meters")
end

run_server(app, "0.0.0.0", 8080)

[etpinard]

Update

dcc_location refresh="callback-nav"

does not work ❌

Translating this "callback-nav" test

see Julia snippet

using Dash

app = dash()

app.layout = html_div() do
    dcc_location(; id = "url", refresh = false),
    dcc_location(; id = "callback-url", refresh = "callback-nav"),
    html_button("click"; id = "callback-btn", n_clicks=0),
    html_div(; id = "content")
end

callback!(app,
          Output("content", "children"),
          Input("url", "pathname")) do pathname
    return if isnothing(pathname) || pathname == "/page-1"
        html_div("1"; id = "div1")
    elseif pathname == "/"
        html_div("base", id = "div0")
    else
        "404"
    end
end

callback!(app,
          Output("callback-url", "pathname"),
          Input("callback-btn", "n_clicks")) do n
    return if n > 0
        "/page-1"
    else
        no_update()
    end
end

run_server(app)

gives

Screencast.from.2023-07-11.11-32-18.webm

where the app hangs after pressing the back button.

[etpinard]

Update

Component as props does not work ❌

using Dash

app = dash()

app.layout = html_div() do
    dcc_checklist(; id="checklist",
                  options=[(label=html_h2("H2 label"), value="h2"),
                           (label="plain label", value="plain")])
end

run_server(app, "0.0.0.0", 8080; debug=true)

lead to