Can't understand the syntax in some Trame examples

[kerim371]

Hi,

There is a very attractive Trame example for integrating VTK with Plotly.

There I can see lines like:

                    view = vtk.VtkRemoteView(
                        render_window,
                        box_selection=("vtk_selection",),
                        box_selection_change=(on_box_selection_change, "[$event]"),
                        **VTK_VIEW_SETTINGS,
                    )

And:

                        html_plot = plotly.Figure(
                            selected=(
                                on_chart_selection,
                                "[$event?.points.map(({pointIndex}) => pointIndex)]",
                            ),
                            **CHART_STYLE,
                        )

What $ means? or $event? ? Does event is accessible from python to view its methods (like dir(event)) and its type (like type(event))?
How to learn to make such structures of code by myself?

[jourdain]

$event comes from here

In this context, selected= is a triggered event on the client side which is captured in the summary here

As you don't necessary know what the $event contains, you can start by doing something_that_trigger_an_event="console.log($event)" and then use the dev console of your browser to explore that $event object so you can extract only the piece you need for the server side using inline JS expression.

[kerim371]

@jourdain thank you!
Good to know.

Haven't work with java-script before and it is very interesting.

P.S. I'm sorry for the late reply