Laravel 8: Call to undefined method Model::contains() - php

Question

I'm using Laravel 8 for my project and in this project and I have created a custom Middleware called Admin that goes like this:
public function handle(Request $request, Closure $next)
{
if (Auth::user()->isAdmin()) {
return $next($request);
}
return redirect('/');
}
And I tried applying it like this:
Route::middleware('admin')->group(function () {
Route::get('test', function () { return "User is authenticated and is an admin."; });
});
And on Kernel.php at $middlewareGroups section:
'admin' => [
'auth',
\App\Http\Middleware\Admin::class
],
So I called the isAdmin() at User Model which simply checks if the role of the user is correct or not:
public function role()
{
return $this->belongsTo(Role::class);
}
public function isAdmin()
{
return $this->role->contains('slug', 'super-admin');
}
But now the problem is, when I go to /test uri, it does not redirect me to ('/') uri and shows me this error:
BadMethodCallException
Call to undefined method App\Models\Role::contains()
So what is going wrong here? How can I fix this issue?
Note that the relationship between roles and users table is One To Many. That's why I wrote role() instead of roles() because each user has only one role.

Answer 1

When you use a belongsTo relationship, laravel will return the model directly and not a collection of models.
When you call:
$this->role
What you get is either null (if the relationship does not exist) or a Role model. You can write your isAdmin function accordingly:
public function isAdmin()
{
return empty($this->role) ? false : $this->role->slug === 'super-admin';
}
You probably copied the code from an example with a Many to many relationship: in that case Laravel will return a collection of models and you can invoke collection methods on it, such as contains

Answer 2

could we see a snip of your Role Model.