如何在创建项目后获取JSON ID

Im using a function to share a collection of bookmarks with other users and i need to get the id after the new item is created in wordpress userpro bookmarks plugin

function share_collection($id,$name,$cbcolor,$user) {
    $user_id = get_user_by( 'email', $user );
    $user_id_current = get_current_user_id();
    $collectionscurrent = $this->get_collections($user_id_current);
    $collections = $this->get_collections($user_id->ID);
    $collections[] = array('label' => $name);

    // transfer bookmarks to shared collection
    foreach($collectionscurrent[$coll_id] as $k => $arr) {
        if ($k != 'label') {
            $collections["This is where id should go"][$k] = 1;
        }
    }

    update_user_meta($user_id->ID, '_wpb_collections', $collections);
}

How do i retrive the id created from $collections[] = array('label' => $name); and use it in the place where i mentioned "This is where id should go"

get_collections function is as follows

function get_collections($user_id) {
    return (array)get_user_meta($user_id, '_wpb_collections', true);
}

Thanks in advance!

It's called array index. Assuming $collections is zero based numerical array without any "holes" in it (hole would be eg index 1 in [0 => 'a', 2 => 'b']), you can use:

$collections[] = array('label' => $name);
$idx = count($collections) - 1;

If it's not numerical or there can be holes, you have to figure out index to use first:

$idx = count($collections);
$collections[$idx] = array('label' => $name);