Validation on array field

[dawidmachon]

Hi,
imagine an array field, which keeps different users.

{
      name: "players",
      label: "Players",
      type: "array",
      fields: [
        {
          name: "user",
          label: "User",
          type: "relationship",
          relationTo: "users",
          hasMany: false,
          required: true,
        },
      validate: ()=>{}
}

How would you write or just give an idea about: Checking if user already is in array?
Problem -> when you are creating document with array field, then all entries are there at once, without _id's, so what only comes to my mind is going each by each and compare against all - but this is super slow and not performant.

Maybe someone has better approach to such topic. How validate on array fields to enforce unique entries inside?

[DanRibbens]

Have you looked at using the filterOptions on your relationship field?

You can use it to limit the options available in the UI and it also enforces this in your API in the built-in validation of the relationship field. This way you won't have a validate function at all.

Your filterOptions will be a function that uses the incoming data and returns { not_in: userIDs } where userIDs is an array of user IDs excluding the assigned value on the field (which you also get as an argument).

Let me know if that helps!

[dawidmachon]

Thanks for good tip. It is much better approach I think.
But it is not solving my issue still. Because in filterOptions you mentioned: "I will get access to the value of field which is currently 'in use'." But that's not true from my perspective.

There are only these options:

key	desc
relationTo	The relationTo to filter against (as defined on the field)
data	An object of the full collection or global document currently being edited
siblingData	An object of the document data limited to fields within the same parent to the field
id	The value of the collection id, will be undefined on create request
user	The currently authenticated user object

So when I'm posting create document from API only on validate function, I got access to current value on field. Or am I missing something?

On top of that - on validate function, I also have issues. Because data always has all fields in array, besides for which iteration value we are currently validating. (which is okay, I suppose). But sibling data contains only 'recent' iteration. So, the only way which right now I'm thinking is checking iv current value exists in data more than once.