Remove DOM nonsense from selection logic

[gjmooney]

Description

Resolve #910

Remove DOM related stuff from layer selection, allow setting selection programmatically

Checklist

• PR has a descriptive title and content.
• PR description contains references to any issues the PR resolves, e.g. Resolves #XXX.
• PR has one of the labels: documentation, bug, enhancement, feature, maintenance
• Checks are passing.
  Failing lint checks can be resolved with:
  • pre-commit run --all-files
  • jlpm run lint

---

📚 Documentation preview: https://jupytergis--981.org.readthedocs.build/en/981/
💡 JupyterLite preview: https://jupytergis--981.org.readthedocs.build/en/981/lite

[github-actions]

👈 Launch a Binder on branch gjmooney/jupytergis/selection-refactor

[github-actions]

Integration tests report: appsharing.space

[martinRenou]

I would keep event-related things out of the model, and handle those in the view only:

Suggested change

	handleItemSelection(
	type: SelectionType,
	item: string,
	event?: { ctrlKey: boolean; button: number },
	): { [key: string]: ISelection } | null {
	set selection(
	newSelection: { [key: string]: ISelection } | null
	) {
	this.localState?.selected?.value = newSelection;
	}
	get selection(): { [key: string]: ISelection } | null {
	return this._selection;
	}

From the view that handles the event:

const currentSelection = model.selection;
if (ctrlKey) {
  model.selection = {...currentSelection, newItem}
}

[mfisher87]

Hey Greg, would you mind updating the PR description to include a bit more information about the motivation for this change, and the title to be a bit more specific? 🙇

[martinRenou]

Thanks!