wp_should_load_block_assets_on_demand(): bool
- Since
- 6.8.0
- Source
wp-includes/script-loader.php:2739
Description
When this function returns true, other functions ensure that blocks only load their assets on-render.
When this function returns false, all block assets are loaded regardless of whether they are rendered in a page.
The default return value depends on the result of wp_should_load_separate_core_block_assets(), which controls whether Core block stylesheets should be loaded separately or via a combined 'wp-block-library' stylesheet.
This only affects front end and not the block editor screens.
Compatibility
- WordPress
- since 6.8.0
- PHP
- 7.4–8.6-dev
- 6.7.7
- 6.8.8
- 6.9.7
- 7.0.4
- 7.1.0
Present in 4 of the 5 tracked releases, added in 6.8.0, and compiles on PHP 7.4 through 8.6-dev.
Return value
bool- Whether to load block assets only when they are rendered.
Performance profile
How much work a call to wp_should_load_block_assets_on_demand() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Trivial
- Scaling
- Constant
- Instructions
- 4–17
- Plugin surface
- 1 hook
- Called by
- 6
Touches nothing outside its own arguments.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 18.
Third-party callbacks on 'should_load_block_assets_on_demand' run inside this call, and their cost is not bounded by anything here.
6 places in core call this, so the cost is paid more often than your own code shows.
What it touches
- hookthird-party callbacks
apply_filters()called directly
Further down the call graph this can also reach query, option, cache, serialize and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.
What one call costs · 4 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_should_load_block_assets_on_demand() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
is_admin() | 4 | is_admin() |
!is_admin() && is_feed() | 7 | is_admin(), is_feed() |
!is_admin() && !is_feed() && wp_is_rest_endpoint() | 10 | is_admin(), is_feed(), wp_is_rest_endpoint() |
!is_admin() && !is_feed() && !wp_is_rest_endpoint() | 17 | is_admin(), is_feed(), wp_is_rest_endpoint(), wp_should_load_separate_core_block_assets(), apply_filters() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 18 instructions, 4–17 executed per call, 3 branches. The work does not change between versions.
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Hooks and filters fired · 1
One hook fires while wp_should_load_block_assets_on_demand() runs, in this order:
- apply_filters( should_load_block_assets_on_demand )filterline 2764 (+25 into the body)
Filters whether block styles should be loaded on demand.
Uses · 5
- is_admin()Determines whether the current request is for an administrative interface page.
- is_feed()Determines whether the query is for a feed.
- wp_is_rest_endpoint()Checks whether a REST API endpoint request is currently being handled.
- wp_should_load_separate_core_block_assets()Checks whether separate styles should be loaded for core blocks.
- apply_filters()Calls the callback functions that have been added to a filter hook.
Used by · 6
- enqueue_block_styles_assets()Function responsible for enqueuing the styles required for block styles functionality on the editor and on the frontend.
- wp_add_global_styles_for_blocks()Adds global style rules to the inline style for each block.
- wp_enqueue_block_style()Enqueues a stylesheet for a specific block.
- wp_enqueue_global_styles()Enqueues the global styles defined via theme.json.
- wp_enqueue_registered_block_scripts_and_styles()Enqueues registered block scripts and styles, depending on current rendered context (only enqueuing editor scripts while in context of the editor).
- wp_load_classic_theme_block_styles_on_demand()Adds hooks to load block styles on demand in classic themes.
Source code
function wp_should_load_block_assets_on_demand() { if ( is_admin() || is_feed() || wp_is_rest_endpoint() ) { return false; } /* * For backward compatibility, the default return value for this function is based on the return value of * `wp_should_load_separate_core_block_assets()`. Initially, this function used to control both of these concerns. */ $load_assets_on_demand = wp_should_load_separate_core_block_assets(); /** * Filters whether block styles should be loaded on demand. * * Returning false loads all block assets, regardless of whether they are rendered in a page or not. * Returning true loads block assets only when they are rendered. * * The default value of the filter depends on the result of {@see wp_should_load_separate_core_block_assets()}, * which controls whether Core block stylesheets should be loaded separately or via a combined 'wp-block-library' * stylesheet. * * @since 6.8.0 * * @param bool $load_assets_on_demand Whether to load block assets only when they are rendered. */ return apply_filters( 'should_load_block_assets_on_demand', $load_assets_on_demand );}Changelog
Introduced in 6.8.0. Unchanged from 6.8.8 through 7.1.0.
Signature, return type and hooks compared across 4 parsed releases.
About this page
- Parsed data
- Generated from the wordpress-develop 7.1.0 tag, from
src/wp-includes/script-loader.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
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