Registration: Add server script, style block type property

[aduth]

Closes #2756
Related: #2751

This pull request seeks to implement and document an alternative approach to enqueueing block assets, integrating new settings into the register_block_type server-side API to help manage context-specific script and style enqueues.

The register_block_type API now supports the following properties:

• editor_script
• editor_style
• script
• style

Assigning one or more of these to registered script or style handles will cause them to be enqueued in the corresponding render contexts (editor-specific or always).

This is intended as part of an effort to coalesce initial block implementations toward the server-side block registration API, as proposed in #2751 to be the default for new blocks.

Testing instructions:

Since this simply builds on existing APIs and no core blocks have been ported to using it (unclear whether this is a direction we'd want to go), there should be no expected impact of these changes.

You may try including a third-party block code and changing to implement with the register_block_type API.

Example:

https://gist.github.com/pento/19b35d621709042fc899e394a9387a54

diff --git a/stars-block.php b/stars-block.php
index da5598c..9ea8cfd 100755
--- a/stars-block.php
+++ b/stars-block.php
@@ -9,15 +9,6 @@
  * Description: Everyone loves stars! Let's add stars (now with more meta)!
  */
 
-function stars_block_enqueue_block_editor_assets() {
-       wp_enqueue_script(
-               'stars-block',
-               plugins_url( 'stars-block.js', __FILE__ ),
-               array( 'wp-blocks' )
-       );
-}
-add_action( 'enqueue_block_editor_assets', 'stars_block_enqueue_block_editor_assets' );
-
 function stars_block_init() {
        // Register the postmeta key that we'll store our data in
        register_meta( 'post', 'stars', array(
@@ -25,5 +16,15 @@ function stars_block_init() {
                'single'       => true,
                'type'         => 'number',
        ) );
+
+       wp_register_script(
+               'stars-block',
+               plugins_url( 'stars-block.js', __FILE__ ),
+               array( 'wp-blocks' )
+       );
+
+       register_block_type( 'stars/stars-block', array(
+               'editor_script' => 'stars-block',
+       ) );
 }
 add_action( 'init', 'stars_block_init' );

[aduth]

A seemingly basic question I wasn't sure of: Are handles required to be unique only between script and style registrations, or for both? i.e. Is it valid to:

wp_register_script( 'foo', /* ... */ );
wp_register_style( 'foo', /* ... */ );

If above is valid, can probably drop the suffix here to remove redundancy.

[westonruter]

They are free to be the same. I do it all the time, and core does it as well. For example, customize-controls:

• Script: https://github.com/WordPress/wordpress-develop/blob/53f1c74e1c55910f9b7e4aebc8033571d3e52df8/src/wp-includes/script-loader.php#L586
• Style: https://github.com/WordPress/wordpress-develop/blob/53f1c74e1c55910f9b7e4aebc8033571d3e52df8/src/wp-includes/script-loader.php#L1065

[aduth]

They are free to be the same.

Thanks! Updated in 5972c9b.

[gziolo]

We will have to update WP-CLI to promote those changes. Please ping me when it is ready to merge so I could open a follow-up PR.

[aduth]

@gziolo I expect this is ready to merge as-is. Do you have any work you'd like to have prepared before I do so?

[gziolo]

It looks like non-breaking change so you can merge anytime. I will update WP-CLI next week to use this simplified API 👍

[gziolo]

@aduth I created wp-cli/scaffold-command#111 for wp scaffold block to include your changes. The output looks great 👍