GatherPress

Last updated July 11, 2026, Version 0.34

• Documentation for developers

GatherPress ships a small shared utility stylesheet (gatherpress-utility-style, sourced from build/utility_style.css) used by GatherPress’s own blocks for things like the gatherpress--is-hidden visibility helper that drives RSVP status switching, tooltip variables, and other primitives shared across the block library.

On the frontend, GatherPress only enqueues the utility stylesheet when a block whose name starts with gatherpress/ is actually rendered, so pages without any GatherPress block don’t pay for the CSS.

Companion plugins and themes can opt their own blocks into the same coverage by adding their block-name prefix to the gatherpress_asset_utility_style_block_prefixes filter.

When to use this filter

Use this filter when your block:

• Renders markup that relies on classes defined in utility_style.css (e.g.
  gatherpress--is-hidden), and
• You’d rather inherit the host plugin’s CSS than maintain your own copy that
  could drift if GatherPress changes a class name.

If your block doesn’t use any of those classes, you don’t need this filter — WordPress will load only the styles your own block registers.

How it works

GatherPress always handles the gatherpress/ prefix itself. The filter is purely additive: whatever array you return is merged with gatherpress/ before the prefix match runs, so you cannot accidentally break GatherPress’s own blocks by replacing the array — you can only add to it.

Example

A companion plugin that ships blocks under the gatherpress-awesome/ namespace can opt them all in with one filter callback:

add_filter(
    'gatherpress_asset_utility_style_block_prefixes',
    static function ( array $prefixes ): array {
        $prefixes[] = 'gatherpress-awesome/';
        return $prefixes;
    }
);

After this runs, any block whose blockName begins with gatherpress-awesome/ will cause gatherpress-utility-style to be enqueued on the page when that block is rendered, alongside GatherPress’s own blocks.

You can add multiple prefixes at once:

add_filter(
    'gatherpress_asset_utility_style_block_prefixes',
    static function ( array $prefixes ): array {
        $prefixes[] = 'gatherpress-awesome/';
        $prefixes[] = 'gatherpress-productions/';
        return $prefixes;
    }
);

Caveats

• The filter is matched as a prefix (via str_starts_with). Pass the
  trailing slash (my-plugin/) so it doesn’t accidentally match unrelated
  namespaces like my-plugin-extra/.
• The utility stylesheet is registered under the handle
  gatherpress-utility-style. If you need it loaded in a non-block context
  (e.g. a settings screen of your own), enqueue it directly by handle.
• Frontend enqueue is gated on render_block for prefixes returned by the
  filter. Blocks rendered exclusively client-side (without ever hitting
  PHP render_block) won’t trigger the enqueue — fall back to enqueuing
  the handle yourself in that case.