make_before_block_visitor()

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

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;
	};
}