Localising a Block

There are 2 main issues in your code:

1. As stated in my answer, the script handle format is <block name with slashes replaced with hypens>-editor-script, so because your block name is my-block/local, then the script handle is my-block-local-editor-script and not my-block-local-edit-script.

2. The correct action name is wp_enqueue_scripts (note the “s”) and not wp_enqueue_script. However, wp_enqueue_scripts would not work because that’s for the front-end (non-admin side). For admin use like the post editing screen at wp-admin/post.php, you can use either admin_enqueue_scripts or a hook specific to the block/Gutenberg editor like enqueue_block_editor_assets.

3. Your JSON translation file should also be using dfbff627e6c248bcb3b61d7d06da9ca9 which is the value of md5( 'build/index.js' ) (no ./). So the file name should instead be my-block-es_ES-dfbff627e6c248bcb3b61d7d06da9ca9.json 🙂

   That value/hash is also what you’d get when you run this via WP-CLI: wp i18n make-json my-block-<locale>.po ./ --no-purge after doing a cd languages in your plugin directory.

How to fix the issues 1 and 2:

1. Change the wp_set_script_translations() line (it’s line 20 in your code) to:

   wp_set_script_translations(
       'my-block-local-editor-script',           // script handle
       'my-block',                               // text domain
       plugin_dir_path( __FILE__ ) . 'languages' // path to your translation files
   );
   

   Or you can use generate_block_asset_handle() to generate the script handle:

   $script_handle = generate_block_asset_handle( 'my-block/local', 'editorScript' );
   wp_set_script_translations( $script_handle, 'my-block', plugin_dir_path( __FILE__ ) . 'languages' );
   

2. Change the add_action( 'wp_enqueue_script', 'script_translations' ); (line 22 in your code) to:

   add_action( 'enqueue_block_editor_assets', 'script_translations' );
   
   // These also work:
   //add_action( 'admin_enqueue_scripts', 'script_translations' );
   //add_action( 'init', 'script_translations' );
   

   Note about using init: Calling register_block_type() will automatically and immediately register the block editor script — see register_block_script_handle(), so init can be used to set the script translations as long as it’s called after calling register_block_type().