I really didn't get what you're actually trying to do and if it's really a Laravel or more a JavaScript issue.

But the error means you're trying to access a Model property while accessing actually a relationship instance.

If you use

$portfolio->pcategory->title

you're accessing the pcategory Model itself (so it will be loaded from the database and you can get its values like title and so on).

If you use

$portfolio->pcategory()

you're accessing the relationship between the two models - which is also a queryBuilder object. That means you can do something like

$portfolio->pcategory()->whereTitle('Hello')->get()

So if you remove the () from your example the error should be gone and something should happen. Unfortunately I have no clue if that's what needs to happen for you ;)

What I'm trying to do is get all the categories to show up depending on the portfolio.

so for example. I have portfolio 1 and that portfolio belongs to the cats category.

So I made a list of my portfolios and I need the category that belongs to them.

Does that help?