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Merged
superdav42 merged 1 commit into from
Jun 9, 2026
Merged

fix(checkout): address deferred checkout review feedback #1362

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29 changes: 28 additions & 1 deletion inc/ui/class-checkout-element.php
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Original file line number Diff line number Diff line change
Expand Up @@ -534,9 +534,14 @@ protected function send_checkout_nocache_headers($atts) {
$headers = apply_filters('wu_checkout_nocache_headers', $headers, $atts, $this);

foreach ($headers as $name => $value) {
$name = trim(str_replace(["\r", "\n"], '', (string) $name));
$value = str_replace(["\r", "\n"], '', (string) $value);

header(sprintf('%s: %s', sanitize_key($name), $value), true);
if ('' === $name || ! preg_match('/^[A-Za-z0-9-]+$/', $name)) {
continue;
}

header(sprintf('%s: %s', $name, $value), true);
}
}

Expand Down Expand Up @@ -848,6 +853,26 @@ function loadCheckout() {
request.send(parts.join('&'));
}

function cleanupFallbackLoad() {
document.removeEventListener('DOMContentLoaded', fallbackLoad);
window.removeEventListener('scroll', fallbackLoad);
window.removeEventListener('resize', fallbackLoad);
}

function fallbackLoad() {
cleanupFallbackLoad();
loadCheckout();
}

function scheduleFallbackLoad() {
if ('loading' === document.readyState) {
document.addEventListener('DOMContentLoaded', fallbackLoad);
} else {
window.addEventListener('scroll', fallbackLoad);
window.addEventListener('resize', fallbackLoad);
}
Comment on lines +867 to +873

@coderabbitai coderabbitai Bot Jun 9, 2026

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⚠️ Potential issue | 🟡 Minor | ⚡ Quick win

Trigger fallback immediately when DOM is already ready.

When document.readyState !== 'loading', the fallback currently waits for a scroll/resize event. In late-execution contexts this can leave viewport defer mode idle until user interaction. Call fallbackLoad() immediately in that branch, and keep listeners only for the loading case.

Suggested patch 
 function scheduleFallbackLoad() {
 	if ('loading' === document.readyState) {
 		document.addEventListener('DOMContentLoaded', fallbackLoad);
-	} else {
 		window.addEventListener('scroll', fallbackLoad);
 		window.addEventListener('resize', fallbackLoad);
+	} else {
+		fallbackLoad();
 	}
 }
🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@inc/ui/class-checkout-element.php` around lines 867 - 873, The
scheduleFallbackLoad function currently waits for scroll/resize when
document.readyState !== 'loading', which can delay fallback activation; change
scheduleFallbackLoad so that if document.readyState === 'loading' it adds
document.addEventListener('DOMContentLoaded', fallbackLoad), otherwise it calls
fallbackLoad() immediately and does NOT add scroll/resize listeners; update
references in scheduleFallbackLoad and ensure only the loading branch registers
listeners while the ready branch invokes fallbackLoad() directly.

}

if (button) {
button.addEventListener('click', function(event) {
event.preventDefault();
Expand All @@ -870,6 +895,8 @@ function loadCheckout() {
loadCheckout();
}
}).observe(root);
} else if ('viewport' === trigger) {
scheduleFallbackLoad();
}
})();
</script>
Expand Down
2 changes: 2 additions & 0 deletions tests/WP_Ultimo/UI/Checkout_Element_Test.php
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Original file line number Diff line number Diff line change
Expand Up @@ -85,6 +85,8 @@ public function test_deferred_output_renders_placeholder_without_nocache_action(
* Test live checkout output path contains explicit no-cache safeguards.
*/
public function test_source_contains_live_checkout_cache_safeguards(): void {
// Source-token assertions intentionally guard cache-safety hooks/headers that
// are otherwise hard to observe reliably in PHPUnit.
// phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
$source = file_get_contents(dirname(__DIR__, 3) . '/inc/ui/class-checkout-element.php');

Expand Down
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