Check existence of a relation in a model

Question

I have a parent model ParentModel, and in it I want to check if ChildModel has a relation, say, user or not.

I try something like:

$relation = "user";
if (isset($this->$relation)){
//    dosomething
}

but the condition is always false even when the relation actually exists.

I know it is a naive question.... :( okay, sue me, I can't find the answer!

Answer 1

Try:

  $relation = "user";
  if (!empty($this->$relation)){
   //    dosomething
  }

Answer 2

I find an answer

isset($this->relations()[$relation])