build_template_part_block_instance_variations

build_template_part_block_instance_variations: 该函数用于为模板部分中的块实例建立变化。它需要两个参数：区块实例的名称和一个变体选项数组。它返回一个块实例的变体数组。

返回模板部分块的实例变化对象数组。

function build_template_part_block_instance_variations() {
	// Block themes are unavailable during installation.
	if ( wp_installing() ) {
		return array();
	}
	$variations     = array();
	$template_parts = get_block_templates(
		array(
			'post_type' => 'wp_template_part',
		),
		'wp_template_part'
	);

	$defined_areas = get_allowed_block_template_part_areas();
	$icon_by_area  = array_combine( array_column( $defined_areas, 'area' ), array_column( $defined_areas, 'icon' ) );

	foreach ( $template_parts as $template_part ) {
		$variations[] = array(
			'name'        => sanitize_title( $template_part->slug ),
			'title'       => $template_part->title,
			// If there's no description for the template part don't show the
			// block description. This is a bit hacky, but prevent the fallback
			// by using a non-breaking space so that the value of description
			// isn't falsey.
			'description' => $template_part->description || ' ',
			'attributes'  => array(
				'slug'  => $template_part->slug,
				'theme' => $template_part->theme,
				'area'  => $template_part->area,
			),
			'scope'       => array( 'inserter' ),
			'icon'        => $icon_by_area[ $template_part->area ],
			'example'     => array(
				'attributes' => array(
					'slug'  => $template_part->slug,
					'theme' => $template_part->theme,
					'area'  => $template_part->area,
				),
			),
		);
	}
	return $variations;
}