Bug fix on accordion active item

[nadijagraca]

Description

Fixing bug on accordion active item:

What to test:
If relevant accordion item opens when navigating from homepage or by typing path in browser.

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[huong-li-nguyen]

Works well - thanks for fixing! 👍

@nadijagraca - for the next time it would be great if you could add some example code snippet to see that the relevant changes work. I wasn't quite sure what I had to test first 😄

For the next reviewer - replace the navigation in the example demo with:

navigation=vm.Navigation(
        nav_selector=vm.NavBar(
            items=[
                vm.NavLink(label="Homepage", pages=["Homepage"], icon="Home"),
                vm.NavLink(
                    label="Analysis",
                    pages={"Title 1": ["Variable Analysis", "Benchmark Analysis"],
                           "Title 2": ["Continent Summary", "Relationship Analysis"]},
                    icon="Stacked Bar Chart",
                ),
            ]
        ),
    ),

Then navigate to relationship-analysis either via clicking on the card on the homepage or by directly changing the path in the URL. What you should see is that the accordion opens accordingly (opens where active page is)

@nadijagraca @l0uden - will we add screenshots to test this? or do the unit tests cover this use case sufficiently?

[antonymilne]

Really nice fix! I didn't test it out but it looks great, thank you for doing it 👍

However, I think there might be a minor bug in it. In this code:

next(
    page_group for page_group, page_members in self.pages.items() if active_page_id in page_members
)

if active_page_id in page_members is always False then this will turn into next of an empty dictionary, which will raise StopIteration and crash. Try this out:

next(x for x, y in dict(a=1).items() if x == "b")

What I'm not sure about is whether this case can ever occur in practice? If I type the URL to a page that doesn't exist in the navigation then is it possible it would trigger this error?