Multisite - sort merged get_posts() queries

Question

I have a multisite (test) installation of WordPress and want to get the posts of every blog.

After hours, I got the solution for that. But now, I have the merged query and like to sort the posts from each blog by date. Now I get the blog1-posts and after all blog1-posts, I get the blog2-posts.

How to sort the array? Here is the code so far:

$custom_posts = array();

$blog_ids = wp_get_sites();

foreach ($blog_ids as $key=>$current_blog) {

    switch_to_blog($current_blog['blog_id']);

    $query = get_posts("posts_per_page=10");

    $custom_posts = array_merge($custom_posts, $query);

    restore_current_blog();

}

//SORT THE $custom_posts BY POST_DATE? HOW? :(

global $post; 

foreach($custom_posts as $post) : setup_postdata($post);

<<< theposts >>>.
.
endforeach;

I hope this is possible to do.

Or is there any better way to reach the goal?

Answer 1

You can try the new (4.7+) wp_list_sort() utility function that's a wrapper for WP_List_Util::sort() that uses usort() or uasort().

Example 1:

Sort by descending post date

$sorted_custom_posts = wp_list_sort( 
    $custom_posts, 
    'post_date', 
    'DESC' 
);

Example 2:

Sort by descending post date and ascending post title

$sorted_custom_posts = wp_list_sort( 
    $custom_posts, 
    [
        'post_date'  => 'DESC',
        'post_title' => 'ASC',
    ]
);

Check the Make post here for more information.