bootstrapping-wp-rest-api-collection.php

<?php
// Make internal REST API requests for all resources the client JS app will need.
$request = new WP_REST_Request( 'GET', '/wp/v2/posts' );
$request->set_query_params( array(
	'per_page' => 5,
	'orderby' => 'title',
	'order' => 'desc',
) );
$response = rest_get_server()->dispatch( $request );
$response = apply_filters( 'rest_post_dispatch', $response, rest_get_server(), $request );
$posts = rest_get_server()->response_to_data( $response, true /* _embed */ );
?>
<script>
wp.api.init().done( function() {
	var posts = new wp.api.collections.Posts();
	posts.reset( <?php echo wp_json_encode( $posts ) ?> );

	// App is now ready to render immediately without having to wait for fetching. 
} );
</script>