Is it possible to sync the frontend model changes with the model in the Deno kernel?

[gergelyszerovay]

Hi,

I tried the following, and expected that the model in Deno will be updated and the change:value event handler will be called:

I ran the first code cell, then clicked on the button a few times, then ran the second code cell.

If I execute model.set('value', 13); from a code cell, the event handler is triggered:

Is there a way to subscribe to the frontend model changes from the code in the Deno kernel? Thanks.

---

Full source code:

import { widget } from "jsr:@anywidget/deno";

let model = await widget({
    state: { value: 0 },
    imports: `
import React from "https://esm.sh/react@18";
import ReactDOM from "https://esm.sh/react-dom@18";

import { createRender, useModelState } from "https://esm.sh/@anywidget/react";
`,
    render: ({ model, el }) => {
        function Counter() {
        	let [value, setValue] = useModelState("value");
        	return <button onClick={() => setValue(value + 1)}>count is {value}</button>;
        }

        return createRender(Counter)({model, el})
	}
});

let v;
model.on("change:value", (x) => {
    console.log(x)
    v = x.detail;
})

model

// ---

console.log(model);
console.log(v);

[manzt]

Thanks for opening the issue! I believe that Deno's jupyter integration only supports broadcasting messages to the frontend (via Deno.jupyter.broadcast) at the moment, but unfortunately not receiving messages. If this API were to be added we could support the bidirectional communication in jsr:@anywidget/deno.

cc: @rgbkrk

[rgbkrk]

Once denoland/deno#23826 is in, it will be pretty smooth to work on the comms receiver.

[manzt]

slick!!! thanks for all your work on runtimelib

[phromo]

Still an issue in deno 2.1.6/anywidget 0.9.13. Had a look at denoland/deno#23826 and my interpretation is that PR did not add frontend->kernel broadcasting for the deno kernel per se, so I assume rgbkrk kinda meant "once that runtimelib is in it will be easier to start working on bidirectional communication".

Correct? If so perhaps the next step is creating the appropriate issue in deno?

[manzt]

Here is the relevant PR to add bidirectional comms:

• feat(jupyter): add handling for comms denoland/deno#24250