WP API V2: Query posts by ACF - wordpress

Question

I would like to query my posts by filtering for a custom meta added with Advanced Custom Fields. It's a boolean meta, so every post will have something like:
GET http://localhost/wp-json/wp/v2/posts
{
...
"acf" : {
"highlight" : true
}
...
}
I'm not able to filter by this meta value, even if I exposed meta_key and meta_value to the REST API in function.php:
function my_add_meta_vars ($current_vars) {
$current_vars = array_merge ($current_vars, array ('meta_key', 'meta_value'));
return $current_vars;
}
add_filter ('rest_query_vars', 'my_add_meta_vars');
But if I try:
GET
http://localhost/wp-json/wp/v2/posts?filter[meta_key]=highlight&filter[meta_value]=true
I see all the posts as if the filter is ignored.

Answer 1

I was able to get this solved with this customization:
add_filter( 'rest_query_vars', function ( $valid_vars ) {
return array_merge( $valid_vars, array( 'highlight', 'meta_query' ) );
} );
add_filter( 'rest_post_query', function( $args, $request ) {
$highlight = $request->get_param( 'highlight' );
if ( ! empty( $highlight ) ) {
$args['meta_query'] = array(
array(
'key' => 'highlight',
'value' => $highlight,
'compare' => '=',
)
);
}
return $args;
}, 10, 2 );
And do a query in this way (highlight is acf boolean)
GET /wp-json/wp/v2/posts?highlight=1