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Script Loader: Defer single-page admin init until DOMContentLoaded (Trac #65103) #78136

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Merged
ellatrix merged 3 commits into from
May 19, 2026
Merged

Script Loader: Defer single-page admin init until DOMContentLoaded (Trac #65103) #78136

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28a04ea
Build: Defer single-page admin init until DOMContentLoaded
westonruter May 11, 2026
674e0d1
Use indentation with flexible nowdoc syntax
westonruter May 11, 2026
ae1f0b8
Replace bare ticket reference with ticket URL
westonruter May 12, 2026
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29 changes: 26 additions & 3 deletions packages/wp-build/templates/page-wp-admin.php.template
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Original file line number Diff line number Diff line change
Expand Up @@ -153,12 +153,35 @@ function {{PREFIX}}_{{PAGE_SLUG_UNDERSCORE}}_wp_admin_enqueue_scripts( $hook_suf
// 2. It initializes the boot module as an inline script.
wp_register_script( '{{PAGE_SLUG}}-wp-admin-prerequisites', '', $asset['dependencies'], $asset['version'], true );

// Add inline script to initialize the app using initSinglePage (no menuItems)
/*
* Add inline script to initialize the app using initSinglePage (no menuItems).
* The dynamic import is deferred until DOMContentLoaded so that all classic
* script dependencies of @wordpress/boot (wp-private-apis, wp-components,
* wp-theme, etc.) have finished parsing and executing before the boot module
* evaluates. Otherwise, a modulepreloaded @wordpress/boot can win the race
* against the classic-script-printing pass on fast CDN-fronted hosts in
* Chrome, evaluating before wp.theme.privateApis is defined and throwing
* "Cannot unlock an undefined object". See <https://core.trac.wordpress.org/ticket/65103>.
*/
$init_js_function = <<<'JS'
( mountId, routes ) => {
const run = async () => {
const mod = await import( "@wordpress/boot" );
mod.initSinglePage( { mountId, routes } );
};
if ( document.readyState === "loading" ) {
document.addEventListener( "DOMContentLoaded", run );
} else {
run();
}
}
JS;
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westonruter marked this conversation as resolved.
wp_add_inline_script(
'{{PAGE_SLUG}}-wp-admin-prerequisites',
sprintf(
'import("@wordpress/boot").then(mod => mod.initSinglePage({mountId: "%s", routes: %s}));',
'{{PAGE_SLUG}}-wp-admin-app',
'( %s )( %s, %s );',
$init_js_function,
wp_json_encode( '{{PAGE_SLUG}}-wp-admin-app', JSON_HEX_TAG | JSON_UNESCAPED_SLASHES ),
wp_json_encode( $routes, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES )
)
);
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