Queries traverse references. Consider this query:

{
  posts: { pid1: {
    title: true,
    author: { name: true }
  } }
}

The first result of this query may be:

{
  posts: { pid1: {
    title: 'Hello, world',
    author: { $ref: 'users.uid1' }
  } }
}

The { name: true } part of the query (which gets the author’s name) is still unfulfilled.

Graffy will then construct a follow-up query to fulfill that, by combining the unfulfilled sub-query with reference path 'users.uid1'.

{
  users: { uid1: { name: true } }
}

If the path has a trailing range key and the root of the sub-query has a range key, the two range keys are merged when constructing this follow-up query. Here's an example:

{
  users: { uid1: {
    name: true,
    posts: [{
      $key: { first: 10 },
      title: true
    }]
  } }
}

Graffy combines the reference ['posts', { authorId: 'uid1', all: true }] with the unfulfilled sub-query [{ $key: { first: 10 }, title: true }] to constructs the follow-up query.

{
  users: { uid1: {
    name: 'Alice',
    posts: { $ref: [
      'posts',
      { authorId: 'uid1', all: true }
    ] }
  } }
}

{
  posts: [{
    $ref: {
      authorId: 'uid1',
      first: 10
    },
    title: true
  }]
}