Wp-rocket: In WP Rocket 3.8.0.1 the Perfmatters Lazyload script gets deferred when Defer JS is enabled, breaking its functionality

[alfonso100]

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Describe the bug
In WP Rocket 3.8.0.1, the Perfmatters Lazyload script gets deferred when Defer JS is enabled, breaking their lazyload functionality.

To Reproduce
Steps to reproduce the behavior:

1. Update to WP Rocket 3.8.0.1
2. Enable Permatters Lazyload, disable WP Rocket Lazyload.
3. Visit the website and see the console error: "Lazyload is not defined". the images won't load
4. Add exclusion: /wp-content/plugins/perfmatters/js/lazyload.min.js
5. Lazyload should be working as expected

Expected behavior
We should automatically exclude Perfmatters lazyload script from being deferred

Screenshots
https://jmp.sh/oGOEKUp

Additional context
Related ticket:
https://secure.helpscout.net/conversation/1372699297/224831/

Backlog Grooming (for WP Media dev team use only)

• [ ] Reproduce the problem
• [ ] Identify the root cause
• [ ] Scope a solution
• [ ] Estimate the effort

[arunbasillal]

@alfonso100 It's a bit unclear from the ticket. But is this something new with 3.8? Or did the issue happen with <3.8 versions too?

I believe L2 directly adds such exclusions with a PR, right?

[GeekPress]

I had a look at the Permatters website and they don't defer their lazyload file:
screenshot

All other JS files are deferred, so I suppose it's voluntary to have excluded their lazyload file.

I'm going to contact them to have more info and to know if they can do the compatibility on their side.

[GeekPress]

FYI, I have just contacted Brian Jackson about this problem.

[brianleejackson]

Hey guys!
Thanks for roping me in. We did some testing today and can see that it appears to have changed with WP Rocket 3.8+. We now have a fix in place on dev, and it will get pushed out in the next update of Perfmatters.

Thanks

[GeekPress]

Thanks @brianleejackson for the confirmation and the fix on your side. I'm going to let our team know about the coming update.