Don't display .ipynb in notebook title

[yuvipanda]

Problem

Notebook files always have the .ipynb extension, so we should not display them. Classic notebook does not.

Classic Notebook:

Retrolab:

Proposed Solution

Trip .ipynb when displaying name of notebook

[jtpio]

Thanks @yuvipanda for the suggestion.

Notebook files always have the .ipynb extension, so we should not display them. Classic notebook does not.

I think it would be fine to indeed not display the extension. And it saves some space in the top area.

One thing to keep in mind too is that RetroLab doesn't need or claim to be a strict copy of the classic notebook UI, so some differences such as this one would be fine.

[yuvipanda]

One thing to keep in mind too is that RetroLab doesn't need or claim to be a strict copy of the classic notebook UI, so some differences such as this one would be fine.

oh yeah, absolutely. Just looking for inspiration :)

[jtpio]

Based on the discussion from other issues (for example https://github.com/jupyterlab/retrolab/issues/259) and the notebook discussion, maybe we'll want to do this to match the classic UI.

The plugin handling the title is defined here:

retrolab/packages/application-extension/src/index.ts

Lines 381 to 447 in 45f879d

	/**
	* A plugin to display and rename the title of a file
	*/
	const title: JupyterFrontEndPlugin<void> = {
	id: '@retrolab/application-extension:title',
	autoStart: true,
	requires: [IRetroShell],
	optional: [IDocumentManager, IRouter],
	activate: (
	app: JupyterFrontEnd,
	shell: IRetroShell,
	docManager: IDocumentManager | null,
	router: IRouter | null
	) => {
	const widget = new Widget();
	widget.id = 'jp-title';
	app.shell.add(widget, 'top', { rank: 10 });
	const addTitle = async () => {
	const current = shell.currentWidget;
	if (!current || !(current instanceof DocumentWidget)) {
	return;
	}
	if (widget.node.children.length > 0) {
	return;
	}
	const h = document.createElement('h1');
	h.textContent = current.title.label;
	widget.node.appendChild(h);
	widget.node.style.marginLeft = '10px';
	if (!docManager) {
	return;
	}
	widget.node.onclick = async () => {
	const result = await renameDialog(docManager, current.context.path);
	// activate the current widget to bring the focus
	if (current) {
	current.activate();
	}
	if (result === null) {
	return;
	}
	const newPath = current.context.path ?? result.path;
	const basename = PathExt.basename(newPath);
	h.textContent = basename;
	if (!router) {
	return;
	}
	const matches = router.current.path.match(TREE_PATTERN) ?? [];
	const [, route, path] = matches;
	if (!route || !path) {
	return;
	}
	const encoded = encodeURIComponent(newPath);
	router.navigate(`/retro/${route}/${encoded}`, {
	skipRouting: true
	});
	};
	};
	shell.currentChanged.connect(addTitle);
	addTitle();
	}
	};

It is also activated and used for text files. Classic shows the extension for other files than notebooks:

So we probably need to special case .ipynb in the plugin, and also make sure renaming is still supported.

Marking as good first issue if someone would like to take a look, thanks!