make_before_block_visitor( array $hooked_blocks, WP_Block_Template|WP_Post|array $context, callable $callback = ‘insert_hooked_blocks’ ): callable

This function’s access is marked private. This means it is not intended for use by plugin or theme developers, only in other core functions. It is listed here for completeness.

Returns a function that injects the theme attribute into, and hooked blocks before, a given block.

Description

The returned function can be used as $pre_callback argument to traverse_and_serialize_block(s), where it will inject the theme attribute into all Template Part blocks, and prepend the markup for any blocks hooked before the given block and as its parent’s first_child, respectively.

This function is meant for internal use only.

Parameters

$hooked_blocksarrayrequired
An array of blocks hooked to another given block.
$contextWP_Block_Template|WP_Post|arrayrequired
A block template, template part, wp_navigation post object, or pattern that the blocks belong to.
$callbackcallableoptional
A function that will be called for each block to generate the markup for a given list of blocks that are hooked to it.
Default: 'insert_hooked_blocks'.

Default:'insert_hooked_blocks'

Return

callable A function that returns the serialized markup for the given block, including the markup for any hooked blocks before it.

Source

function make_before_block_visitor( $hooked_blocks, $context, $callback = 'insert_hooked_blocks' ) {
	/**
	 * Injects hooked blocks before the given block, injects the `theme` attribute into Template Part blocks, and returns the serialized markup.
	 *
	 * If the current block is a Template Part block, inject the `theme` attribute.
	 * Furthermore, prepend the markup for any blocks hooked `before` the given block and as its parent's
	 * `first_child`, respectively, to the serialized markup for the given block.
	 *
	 * @param array $block        The block to inject the theme attribute into, and hooked blocks before. Passed by reference.
	 * @param array $parent_block The parent block of the given block. Passed by reference. Default null.
	 * @param array $prev         The previous sibling block of the given block. Default null.
	 * @return string The serialized markup for the given block, with the markup for any hooked blocks prepended to it.
	 */
	return function ( &$block, &$parent_block = null, $prev = null ) use ( $hooked_blocks, $context, $callback ) {
		_inject_theme_attribute_in_template_part_block( $block );

		$markup = '';

		if ( $parent_block && ! $prev ) {
			// Candidate for first-child insertion.
			$markup .= call_user_func_array(
				$callback,
				array( &$parent_block, 'first_child', $hooked_blocks, $context )
			);
		}

		$markup .= call_user_func_array(
			$callback,
			array( &$block, 'before', $hooked_blocks, $context )
		);

		return $markup;
	};
}

Changelog

VersionDescription
6.5.0Added $callback argument.
6.4.0Introduced.

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