Translations in JS Files
You need to «tell» WP that your script has a translation, and specify which text domain (ID) should be used for this translation. This is done using the wp_set_script_translations() function.
So, the registration of your script with translation should look like this:
wp_register_script( ‘my-handle’, plugins_url( ‘/js/my-file.js’, __FILE__ ) );
wp_set_script_translations( ‘my-handle’, ‘my-domain’ );
The wp_set_script_translations() function adds a dependency on the main script for wp-i18n and includes the .json file.