Type with only empty properties should be rendered

[Chris Müller]

A type without one property set is not rendered in the schema markup. But this is necessary, e.g. for the WebPage type of the home page, because no breadcrumb is available here.

Example:

$schemaManager = GeneralUtility::makeInstance(SchemaManager::class);
$schemaManager->addType(new WebPage());
$schemaManager->renderJsonLd();

The current output is:

<script type="application/ld+json">[]</script>

It should be:

<script type="application/ld+json">{"@context": "http://schema.org", "@type": "WebPage"}</script>