Preventing double loading JS scripts (like React) when developing for Gutenberg

Any WordPress-packaged scripts enqueued properly via wp_enqueue_script won’t load multiple times. If two different plugins rely on the same dependencies, thanks to the enqueue logic, those dependencies will only be loaded once.

create-guten-block only contains javascript relevant to the custom block itself, and sets wp-blocks, wp-i18n, and wp-element (the abstraction layer WP uses on top of React) as its dependencies. See /src/init.php of the generated block code.