serialise layouts (e.g. persist layouts between sessions)

[oliver-sanders]

Can we serialise Lumino layouts?

This might be useful to:

• Persist layouts between sessions (e.g. on the filesystem or in LocalStorage).
• Define default layouts.
• Test Lumino applications.

Note, the app would need its own logic to restore the components within the Lumino layout, this is beyond the scope of Lumino itself.

Problem

With Lumino, we can save layouts in a format that we can restore later:

const layout = dockPanel.saveLayout()
dockPanel.restoreLayout(layout)

This works great, however, it is difficult to persist these layouts beyond the life of the session because they contain references to HTML elements:

>> layout.main.children[0].widgets[0].node
<div id="widget3" class="lm-Widget content lm-DockPanel-widget" role="tabpanel" aria-labelledby="tab-key-1-0" style="position: absolute; cont…: 300px; height: 996px;">

And cannot be easily serialised:

>> JSON.stringify(layout)
Uncaught TypeError: cyclic object value

Proposed Solution

The ability to reconstruct a layout in a new session.

E.g, something along the lines of:

function serialise(layout) {}

function deserialise(layout, context) {}

[biru-codeastromer]

@oliver-sanders hey sir, can i work on this issue please

[oliver-sanders]

@biru-codeastromer, you are most welcome to work on this issue from my perspective, however, I am not actually involved with the lumino project, I just opened this issue.

[krassowski]

JupyterLab already implements logic state restoration. Maybe it could be made more generic and moved into lumino. This would be a larger effort.

[oliver-sanders]

@krassowski, interesting, do you know where in the code Jupyter Lab does this? It would be a useful reference for other applications.

[krassowski]

See ILayoutRestorer and friends.