Okay, so I noticed that this explore page includes all the users (including current user and users we already follow), which in my opinion doesn't make much sense. Disclaimer: I know it's because Jeff has to wrap things up, I'm just writing this for someone who might want to implement this logic in their app. So, we only want the users we don't follow on our Explore page and we want to see them as well as their latest tweet. Here's how the controller should look like:

 public function __invoke()
    {
        $users = User::with('tweets')
            ->whereNotIn(
                'id', auth()->user()->follows()->pluck('id')
                ->prepend(auth()->user()->id)
            )
            ->paginate(15);

        return view('explore', ['users' => $users]);
    }

First things first, I eager-loaded the tweets. Now, this all seems good, we avoided the N+1 issue with eager-loading, but notice that we still eager load ALL of the tweets from each user, even though we don't need them. So, yes, we are performing only 2 queries here, but we're still loading a bunch of tweets we don't need into memory. Unfortunately, my first thought was: okay, I'll just constrain the eager load to only the first tweet (remember, we don't need to order them by created_at desc since we're already doing that on the relationship method, so it's one chaining less). So, I ended up with something like this:

$users = User::with(['tweets' => function($query) {
            $query->limit(1);
        }])
            ->whereNotIn(
                'id', auth()->user()->follows()->pluck('id')
                ->push(auth()->user()->id)
            )
            ->paginate(15);

Good, right? Paginate all the users for me and for each user eager-load the tweets, but only give me one tweet per user. Wrong! It will give you only the last tweet from the entire table, it won't limit it to 1 tweet per user. first() and take() don't work here either (it also says in the docs).

So, one solution is to eager load without constraint Yes, it'll take up more memory, but it's better than running 16 queries per page load, it's not the end of the world. The "proper" solution that gets rid of both the N+1 query and loading the unnecessary data is to leverage Eloquent relationship between User and Tweet once again, but instead of writing a one-to-many, you'll make a one-to-one relationship.

// User model

public function latestTweet()
{
        return $this->hasOne(Tweet::class)->latest();
}

And finally, go back to your controller and eager-load this latestTweet relationship and you're good to go.

Now, I'd just appreciate if someone more experienced could tell me if I'm an idiot or this actually makes sense. :) thanks

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