Fix handling IMG tags with JS-based lazy-loading#1785
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westonruter wants to merge 4 commits intotrunkfrom
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Fix handling IMG tags with JS-based lazy-loading#1785westonruter wants to merge 4 commits intotrunkfrom
westonruter wants to merge 4 commits intotrunkfrom
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westonruter
added
[Type] Bug
westonruter
commented
Jan 9, 2025
| return false; | ||
| } | ||
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| // Abort if the srcset is a data: URL since there is nothing to optimize. |
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Well, there could be something to optimize. We can't preload the URL, but we could still add fetchpriority=high to the IMG.
westonruter
commented
Jan 9, 2025
| private function process_img( OD_HTML_Tag_Processor $processor, OD_Tag_Visitor_Context $context ): bool { | ||
| $src = $this->get_valid_src( $processor ); | ||
| if ( null === $src ) { | ||
| if ( ! $this->is_img_with_valid_src_and_srcset( $processor ) ) { |
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As noted below, this may be too conservative. We could still process this IMG. It's just we would skip any parts related to preloading the src or srcset.
Codecov ReportAttention: Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## trunk #1785 +/- ##
==========================================
+ Coverage 57.43% 57.52% +0.08%
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Files 84 84
Lines 6508 6519 +11
==========================================
+ Hits 3738 3750 +12
+ Misses 2770 2769 -1
Flags with carried forward coverage won't be shown. Click here to find out more. ☔ View full report in Codecov by Sentry. |
westonruter
modified the milestones:
image-prioritizer 0.4.0,
image-prioritizer n.e.x.t
westonruter
modified the milestones:
image-prioritizer 1.0.0-beta1,
image-prioritizer n.e.x.t
westonruter
modified the milestones:
image-prioritizer 1.0.0-beta3,
image-prioritizer n.e.x.t
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On quite a few sites I found JS-based lazy-loading causing problems with Image Prioritizer. In particular, the Avada theme's Fusion Images lazy-loading functionality replaces
srcsetwithdata-srcsetbut it doesn't change thesrc, for example:This was resulting in an erroneous preload link being added, in particular the
imagesrcsetis pointing to adata:URL:So this PR adds checks to make sure that if an
IMGhas such asrcsetit is also excluded from processing.In a future PR we could consider undoing such JS-based lazy-loading, rewriting
data-srctosrc,data-srcsetback tosrcsetand so on, and then to process theIMGas normal. This would have a dramatic improvement to LCP especially when the such JS-based lazy-loading is being done for images in the initial viewport, especially for anIMGwhich is the LCP element. See #1746.