How to force JSONEditor to redraw after the underlying dict is updated

Panel
1

Hi,

Is it possible to force JSONEditor to redraw the moment its underlying dict is updated. For example, with the following code

class JSONEditorDemo(param.Parameterized):
    config = param.Dict(default={"data": 1}, doc="config")

    def panel(self):
        return pn.widgets.JSONEditor.from_param(self.param.config)

demo = JSONEditorDemo()
demo.panel()

it will show a JSONEditor in the current cell.

If some other process modified the underlying dict, e.g. demo.config["data"]=0, is it possible to force the existing widget to update its content to show the updated value?

2

I would not say it is a pretty solution, but this will work.

The class will create a new editor every time the config changes. This is done inside a method that is wrapped in a pn.panel to be able to update every time config changes.

The demo.param.trigger("config") is needed because updating a value inside a dictionary does not update trigger param.depends. Alternative it could have been done with demo.config = {'data': 0}

import panel as pn
import param

pn.extension("jsoneditor")


class JSONEditorDemo(pn.viewable.Viewer):
    config = param.Dict(default={"data": 1}, doc="config")

    @param.depends("config", on_init=True)
    def _update_editor(self):
        self.editor = pn.widgets.JSONEditor.from_param(self.param.config)
        return self.editor

    def __panel__(self):
        return self._update_editor


demo = JSONEditorDemo()
pn.panel(demo)

demo.config["data"] = 0
demo.param.trigger("config")

1 Like
3

Thanks for the solution :grin:. It seems like Panel cannot tell if a dictionary is updated in the backend, so a manual trigger is necessary in this case.

1 Like