Does it still make sense to refetch queries on "focus" by default?

[ilyasmez]

Hello 👋

Right now, React Query has refetchOnWindowFocus set to true by default. And the default "focus" detection logic looks like this:

query/src/core/focusManager.ts

Lines 58 to 74 in 5285479

	private setDefaultEventListener() {
	if (!isServer && window?.addEventListener) {
	this.setEventListener(onFocus => {
	const listener = () => onFocus()
	// Listen to visibillitychange and focus
	window.addEventListener('visibilitychange', listener, false)
	window.addEventListener('focus', listener, false)
	return () => {
	// Be sure to unsubscribe if a new handler is set
	window.removeEventListener('visibilitychange', listener)
	window.removeEventListener('focus', listener)
	}
	})
	}
	}
	}

As you can see, the focus manager listens to visiblitychange and focus events by default.

💡 I'm wondering if it makes sense to stop listening to focus event and listen only to visibilitychange. 💡

To me, it seems that we're supporting both events just for historical reasons, as visiblitychange wasn't fully supported in some old browsers which are dropped now (e.g. IE11 💀).

The focus event has many pitfalls, as it's triggered in the following cases:

• Navigating between DevTools and the app.
• When closing an alert or confirm dialog.
• File upload dialogs.
• When interacting with an iframe.

And this can result in a bad UX.

I know that it's possible to customize this event as shown here: https://tanstack.com/query/v4/docs/react/guides/window-focus-refetching#custom-window-focus-event
But this discussion is about the default behavior. I think the library should provide the best possible experience out of the box.

[TkDodo]

To me, it seems that we're supporting both events just for historical reasons, as visiblitychange wasn't fully supported in some old browsers which are dropped now (e.g. IE11 💀).

That's a very good point I actually wasn't aware of. We're updating our browserlist for v5, so this seems like a good moment to reflect on if that is still needed.

I'm aware of the "alert issue" - I didn't know that the focus event was the culprit.

What you are saying makes sense to me - would you like to contribute this change to the v5 branch?

[TkDodo]

I guess this would also help with the input type file problem?

• Input type=file dialogue triggers windows focus refetch #2960

[kyawthura-gg]

@TkDodo I would like to contribute. can you please give me hint or assign me to that issue? Thank you 🙏 .

[ilyasmez]

I guess this would also help with the input type file problem?

• Input type=file dialogue triggers windows focus refetch #2960

Yes it would, on Chrome for MacOS at least. I'm not sure if there are some browsers that change the visibility state of the document if the file picker is open.

@kyawthura-gg I already have a fix for this. I'll open a PR today and request your review as well if you would like to (co)contribute.

[kyawthura-gg]

Yes, sure.

[ilyasmez]

I've finally had the time to work on this fix. The PR is here: #4805