Why are nodes and edges optional?

[typeofweb]

After introspecting the generated schema, we get the following type for Posts:

type RootQueryToPostConnection {
  edges: [RootQueryToPostConnectionEdge]
  nodes: [Post]
  pageInfo: WPPageInfo
}

Why are all these fields optional instead of required?

type RootQueryToPostConnection {
  edges: [RootQueryToPostConnectionEdge!]
  nodes: [Post!]
  pageInfo: WPPageInfo!
}

[jasonbahl]

@mmiszy Thanks for the question.

Edges and Nodes are optional because there's no guarantee that there will be data to return. It's possible that no data of that Type has been published yet, or that the data for that connection is private and the requesting user doesn't have proper permission to view the data.

[typeofweb]

Makes sense, but wouldn't that just result in an empty array being returned?

[jasonbahl]

Yes, which is more ideal than en error being returned. If there was no data to return, but the Schema marked it as required, then the response would include errors, but not having published data of a Type is not an error.

[typeofweb]

Maybe I'm missing something, but if you defined the schema as follows:

type RootQueryToPostConnection {
  nodes: [Post!]!
}

This would still be a valid response:

{
  "nodes": []
}

Wouldn't it?

[jasonbahl]

@mmiszy, yes, I suppose it would be valid still.

I've confirmed in WPGraphQL directly.

The general connections Schema has been around for a while in WPGraphQL, so I can't say for certain what all went into the thought process, but I believe I modeled a lot of the WPGraphQL Schema off of Github's design for connections, and they do not have their edges/nodes set to nonNull.

Is there a particular reason you believe this change would be beneficial? Would love to learn more about your experience with requiring edges/nodes vs leaving them nullable.

[typeofweb]

I believe it would make DX better, especially when using TypeScript. Currently, to render a list of posts I have to do the following:

<ul>
  {data?.posts?.nodes?.map((post) => (
    <li key={post?.id}>{post?.title}</li>
  ))}
</ul>

Even though the data is surely there!