how to limit a reference to just one entry in Studio reference input side versus the default as-many-entries-as-you-fill-in-an-array?

Does anyone have a quick pointer/guidance on how to limit a reference to just one entry in Studio

reference

input side versus the default as-many-entries-as-you-fill-in-an-array?

For instance, this is the default:

{

name: ‘related_post’,

title: ‘Post’,

type: ‘array’,

of: [{ type: ‘reference’, to: { type: ‘post’ } }]

}

And I’m perfectly fine with an array of a single reference. I assumed I could add something to the

of

portion, but I didn’t see clear documentation on what’s possible there.
I also didn’t think this was a validation situation either since it’s a limit on adding more. But I could be wrong if that is actually the correct approach.

Is a single reference only done via a unique object?

Guidance or recommendation would be super appreciated.

What’s wrong with just doing this?

Yup, that was it . I didn’t realize I can just direct reference like that. Much appreciated!