I figured something out based on what I found at this postpost.
Basically I need a plugin that listens for when the REST response is about to go out. The plugin code would be similar to the following:
function ag_filter_post_json($response, $post, $context) {
$tags = wp_get_post_tags($post->ID);
$response->data['tag_names'] = [];
foreach ($tags as $tag) {
$response->data['tag_names'][] = $tag->name;
}
return $response;
}
add_filter( 'rest_prepare_post', 'ag_filter_post_json', 10, 3 );
It adds the tag names as a new property called tag_names
. The rest of the heavy lifting is done by the wp_get_post_tags
function.