PHP instanceof for traits

Question

What is the proper way to check if a class uses a certain trait?

Answer 1

I just found how Laravel solves this and thought I'd share it here. It uses class_uses beneath but goes through all the parents to find all the traits recursively.

It defines a helper function called class_uses_recursive:

function class_uses_recursive($class)
{
    if (is_object($class)) {
        $class = get_class($class);
    }

    $results = [];

    foreach (array_reverse(class_parents($class)) + [$class => $class] as $class) {
        $results += trait_uses_recursive($class);
    }

    return array_unique($results);
}

function trait_uses_recursive($trait)
{
    $traits = class_uses($trait);

    foreach ($traits as $trait) {
        $traits += trait_uses_recursive($trait);
    }

    return $traits;
}

And you can use it like this:

in_array(MyTrait::class, class_uses_recursive($class));

You can see how they use it to check if a model implements the SoftDeletes trait here:

public function throughParentSoftDeletes()
{
    return in_array(SoftDeletes::class, class_uses_recursive($this->throughParent));
}