How to use Default Models in relationships in Laravel

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The belongsTo, hasOne, hasOneThrough, and morphOne relationships allow you to define a default model that will be returned if the given relationship is null.

Let’s say we have a relationship in Post model:

public function author()
{
    return $this->belongsTo('App\Author');
}

And then somewhere in Blade file we have this:

{{ $post->author->name }}

Now, what if some post doesn’t have author? Meaning posts.author_id is NULL. You will get an error “Trying to get property of non-object”, meaning that there’s no $post->author, which is correct.

How I handle it usually:

{{ $post->author->name or 'Anonymous' }}

Or you can perform a check for existence:

@if ($post->author)
  {{ $post->author->name }}
@else
  Anonymous
@endif

What if I told you there’s a better way?

Apparently, Eloquent relationships allow to define “default” models, in case the model wouldn’t return anything.

public function author()
{
    return $this->belongsTo('App\Author')->withDefault();
}

In this example, the author() relation will return an empty App\Author model if no author is attached to the post.

Furthermore, we can assign default property values to that default model.

/**
 * Get the author of the post.
 */
public function user()
{
    return $this->belongsTo('App\Models\User')->withDefault([
        'name' => 'Anonymous',
    ]);
}

/**
 * Get the author of the post.
 */
public function user()
{
    return $this->belongsTo('App\Models\User')->withDefault(function ($user, $post) {
        $user->name = 'Anonymous';
    });
}

By using this structure, you don’t need to check anything in Blade anymore – just have the same