RFC: Update refocusExchange to utilize Page Visibility API

[kitten]

See: #1055

Summary

There are known issues that occur with the focus event:

• iframe can cause the focus event to fire numerous times if the user interacts with the iframe and then back with the current document
• DevTools can cause the focus event to fire numerous times if the user/developer interacts with the DevTools and then back with the document. (A very common case for developers)
• A developer fires a focus event (ie. node.dispatchEvent(new CustomEvent('focus', { bubbles: true}))). This case seems less likely but still a side-effect of the current implementation.

We may also want to check what other libraries, like swr, are doing.

Proposed Solution

• Check whether the Page Visiblity API can help with this
• Reimplement refocusExchange with the new API
• Preserve IE11 support with fallbacks, polyfills, or workarounds (or an alternative approach entirely?)

[JoviDeCroock]

I have just verified the Page visbility API on IE11 (Windows 10) and it works correctly as mentioned on MDN.

In SWR they are using the same API for revalidation.

[tatchi]

Hi,

Has anyone started to work on this? If not, I would love to give it a shot :)

[JoviDeCroock]

Hey @tatchi,

Noone has picked this up as far as I'm aware, feel free to give it a shot. In case you're not sure or want some guidance you can put it up as draft and I'd be glad ot help out where I can.