render_block -> core/heading ["attrs"]["level"] only with <h1> headings

[nicmare]

When i debug the render_block filter on core/heading block, i've noticed there is an attrs array with "level" entry for only h1 headline. Then "level" has value of "1". When i change h1 to h2 or h3 the "level" entry is missing. Is this on purpose?! WordPress 5.2.2

[shawncook]

Noticing this as well. I'm able to target core/heading blocks with a level of 1, but I can't target 2 through 6.

[danbowles]

Ended up implementing a regex:

if (
	'core/heading' === $block['blockName']
) {
	preg_match( '/\n*<(?P<level>h[1-6])/si', $block['innerHTML'], $matches );
	$heading_level = ! empty( $matches['level'] ) ? 'block--heading-' . $matches['level'] : '';
	$wrapped_block_content = sprintf(
		'<div class="block--heading-container '. $heading_level .'">%s</div>',
		$block_content
	);
}
return ! empty( $wrapped_block_content ) ? $wrapped_block_content : $block_content;

This will produce:
<div class="block--heading-container block--heading-h1/h2/etc">

[certainlyakey]

Clearly a bug. Makes creating a table of contents or page headings menu more difficult.

This is even more strange considering that by default Gutenberg only displays h2-h4 as level options in the floating toolbar (assuming that h1 should not really be used within post content).

[talldan]

I'm not able to reproduce fully what's described using the following code:

function my_test_render_callback( $content, $block ) {
	if ( 'core/heading' !== $block['blockName'] ) {
		return $content;
	}

	return json_encode( $block[ 'attrs' ] );
}

add_filter( 'render_block', 'my_test_render_callback', 10, 2 );

I do indeed see that there's no level attribute when the level is set to 2, but at other levels it works ok.

This is happening because the default level is 2, and default attributes aren't applied for static blocks when trying to access them in PHP. It looks like this is tracked in #2751, I think there's a long term effort to improve this, part of which is moving all the attribute definitions to .json files so that they can be read by PHP.

I'll close this if that's ok, as I think this is adequately tracked in #2751.

[swinggraphics]

Default attributes aren't applied for static blocks when trying to access them in PHP

Aaaargh. Gutenberg: making life harder in PHP, and requiring a lot more skill and hoop-jumping to access in JS. The linked issue #2751 is Closed, as well. 😢