Why doesn't Laravel sort() work?

Question

PHP

It is necessary to display dialogs, while the essence of chats, as such, is not present. There are just messages in which sender_id and receiver_id. Now you need to display a list of chats. Then I came across a problem that it is not possible to sort users by the latest message, tell me what is wrong with the code?

$users = $users->sort(function ($user){
            return $user->lastMessage->created_at->toDateTimeString();
        });

Displays generally in the left order, there is no dependence on the date of the last message.

Answer 1

Of course you can. You do a nested iteration of arrays through foreach or whatever is more convenient for you. Add the check if field_with_brand_name === Ferroz to the enumeration, if true, then add the data to the resulting array.

Answer 2

->sortByDesc('lastMessage.created_at')
?

Answer 3

Because you need to pass a callback to the sort function by analogy with the uasort PHP function, there are some peculiarities there.
You need to use sortBy / sortByDesc.
https://github.com/laravel/framework/blob/6.x/src/...