focusOut method
void
focusOut()
← key: collapse an expanded folder, else step out to the parent.
Implementation
void focusOut() {
final id = focused;
if (id == null) return;
final n = node(id);
if (n != null && n.isFolder && n.hasChildren && _expanded.contains(id)) {
_expanded.remove(id);
notifyListeners();
return;
}
final ancestors = TreeOps.ancestorsOf<T>(_roots, id);
if (ancestors.isNotEmpty) {
_focused = ancestors.last;
notifyListeners();
}
}