Conditionally adding relationships using `whenLoaded()` in Laravel.
Jul 19, 2025 am 01:32 AMwhenLoaded() is a method in Laravel for conditional processing of loaded relationships. It executes a callback function when the specified relationship has been loaded, avoiding triggering N 1 queries or errors when not loaded. For example, in API resources, only fields are added when the relationship exists, associated data is processed without forced loading, and secure access to the attributes in combination with optional(). When using it, make sure that the relationship name is accurate and preloaded through with() or dynamic access. The closure receives the relationship results (model or collection) for optimization performance and data transformation.
In Laravel, when you're working with Eloquent relationships and need to conditionally load or add a relationship to a model based on whether it was loaded from the database, whenLoaded()
is a useful method. It helps avoid unnecessary data fetching and keeps your code clean by checking if a relationship has already been loaded.

Here's how and why you'd use it.
What does whenLoaded()
actually do?
The whenLoaded()
method checks if a specific relationship was loaded on a model. If it was, it lets you run a callback that modifies or augments that relationship.

For example:
$user->whenLoaded('profile', function ($profile) { // This only runs if the profile relationship was loaded return $profile->is_complete ? 'Complete' : 'Incomplete'; });
This avoids trying to access $user->profile
when it might not be available (like in cases where it wasn't eager-loaded), which could lead to N 1 query issues or errors.

When should you use whenLoaded()
?
You'll typically reach for whenLoaded()
in scenarios like:
- Transforming API responses — only include extra fields if related models are present.
- Avoiding N 1 queries — only process relationships that were already eager-loaded.
- Conditional logic in resource collections or transformers — adjust output based on what data is available.
Let's say you have a user resource that sometimes include their posts. You want to count comments only if posts are loaded:
$user->whenLoaded('posts', function ($posts) { return $posts->flatMap->comments->count(); });
That way, you're not forcing a load of posts just to count comments.
How to use whenLoaded()
in real code
Here's a more practical example inside a Laravel resource collection:
public function toArray($request) { Return [ 'id' => $this->id, 'name' => $this->name, 'email' => $this->email, 'latest_post_title' => $this->whenLoaded('posts', function ($posts) { return optional($posts->first())->title; }), ]; }
A few notes here:
- We're using
optional()
to safely access the first post's title without throwing an error if there are no posts. - The
latest_post_title
key will only appear if theposts
relationship was loaded.
If you don't use whenLoaded()
, you might end up with either missing data or unexpected queries being triggered behind the scenes.
A few gotchas and tips
- Make sure the relationship name passed to
whenLoaded()
matches exactly — it's case-sensitive and must match the method name on the model. -
whenLoaded()
doesn't load the relationship for you — it only acts if it was already loaded viawith()
or dynamically accessed earlier. - It works great in combination with Laravel's conditional attributes (
when()
andmergeWhen()
).
Some common mistakes:
- Trying to use
whenLoaded()
expecting it to lazy-load the relationship — it won't. - Forgetting that the closure receives the relationship result directly (ie, a Collection or Model, depending on the type of relationship).
So if you're working with a hasOne
or belongsTo
, you'll get a single model or null
. With hasMany
, you'll get a collection.
Using whenLoaded()
properly can make your code cleaner and more efficient, especially when building APIs or complex data transformations. It's one of those small tools in Laravel that feels simple but makes a big difference in avoiding performance pitfalls.
Basically that's it.
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