Unload event handler in buddypress-notifications.js breaks bfcache

[westonruter]

The use of the unload event handler ​in buddypress-notifications.js is currently making the Notifications page ​ineligible for bfcache. This event is unreliable, and it will be ​deprecated and removed from Chrome. A more appropriate event should be used, such as pagehide. This was done in core with ​#55491.

The addition of unload goes far back to commit ​193538d on July 12, 2016 in buddypress/next-template-packs and ​merged for 3.0.0-RC1.

Enabling bfcache in WordPress while being logged-in is enabled via the ​No-cache BFCache which is a feature plugin to implement ​#63636.

Aside: I blogged about bfcache in WordPress in this post: ​Instant Back/Forward Navigations in WordPress.

[espellcaste]

Thanks! I was not aware of that. We will patch this up. Since it is not super urgent, IMO. I'll schedule to BP 15.0.

[vapvarun]

Attaching a patch that replaces the unload event with pagehide in buddypress-notifications.js.

The Change:

// Before
$( window ).on( 'unload', this.resetFilter );

// After
$( window ).on( 'pagehide', this.resetFilter );

Why This Matters:

• The unload event is deprecated and will be removed from Chrome
• Using unload makes pages ineligible for bfcache (back/forward cache)
• pagehide is the modern replacement that allows bfcache to work properly
• WordPress core made the same change in ​#55491

Testing:

Verified on a local BuddyPress 15.0.0-alpha installation:

• Confirmed pagehide event handler is registered (1 handler)
• Confirmed unload event handler is NOT registered (0 handlers)
• Confirmed resetFilter() function works correctly - filter value resets from 5 to 0
• Notifications page loads and functions normally

The functionality remains identical - the filter is still reset when leaving the page.

[espellcaste]

In 14180:

Administration: Remove deprecated unload event handlers with pagehide.

For a more deeper understanding about this change, refer to ​https://core.trac.wordpress.org/ticket/55491.

Props westonruter and vapvarun.

See #9299 (14.0).

[espellcaste]

Moving this to 14.5 instead.

[espellcaste]

In 14181:

Administration: Remove deprecated unload event handlers with pagehide.

For a more deeper understanding about this change, refer to ​https://core.trac.wordpress.org/ticket/55491.

Props westonruter and vapvarun.

Fixes #9299 (trunk).