Best practices for paginating nested query results?

GraphQL API
1

Hi all,

I was wondering how you handle queries that have nested lists that need to be paginated to get everything. By “how do you handle…?” I mean how do you keep track of the cursors and feed them to the “after” filter and ensure that you get the full set of records for an initial query?

I’m going to give a very simple example query, but I want to be clear that I’m not looking for ways to fix or improve this specific query. I’m looking more for high level concepts and best practices. Here’s a simple orders/line_items query, and I’m requesting the first 5 orders, and for each order I’m requesting the first 5 lines:

query {
  orders(order_date_from: "2020-09-14") {
    request_id
    complexity
    data (first: 5) {
      pageInfo {
        hasNextPage
        endCursor
      }
      edges {
        cursor
        node {
          id
          order_number
          order_date
          line_items (first: 5) {
            pageInfo {
              hasNextPage
              endCursor
            }
            edges {
              cursor
               node {
                 sku
                 quantity
                 fulfillment_status
               }
             }
           }
        }
      }
    }
  }
}

There is a potential here that all lists will need to be paginated to get the full set of results on each, and in this example, that would be 6 different lists: one for the top-level list of orders, and then each line_items list in each order.

What is the best way to handle this?

I know one option would be to split it into multiple queries. I could first run the top level “orders” query without the line_items, and then I could feed the order_id from each order into an “order” query to get the line_items for just that order, paginating the line items there as needed. But that seems like it would be very slow in inefficient because I would be, in this case, sending at least 6 different queries to achieve the same result set as the original query.

Actually… is that the only option? Having 6 different endCursors, I can’t even wrap my head around what the next query would look like. How would I even supply 5 cursors in the “after” filter to get the next page of each set of line_items?

Hopefully someone out there has some enlightenment for me, because I’ve been noodling around on this for quite some time, and I can’t come up with how I would get the subsequent pages of orders and line_items.

Thanks,
Jeremy