Filter nested objects in WPGraphQL - wordpress

Question

I'm using WPGraphQL to interact with a vanilla wordpress backend. gatsby-source-wordpress is used as a client.
What I would like to achieve with my query:
for a list of category ids, give me a list of posts that belong to each category
each list of posts should be filtered (posts not having a certain id, etc), and limited to a certain number. The filter/limit params would be the same for each category.
Now when I'm constructing my query, it seems like I can only filter the outer node (category), but not the attached post node:
// syntax from the gatsby-source-wordpress plugin
// https://github.com/gatsbyjs/gatsby/tree/master/packages/gatsby-source-wordpress
query MyQuery {
allWpCategory(filter: {id: {in: ["dGVybTo0Mg=="]}}) {
nodes {
posts { // cannot filter here 🥲
nodes {
title
id
}
}
}
}
}
I tried adding the filter in different locations, without success. Searched for solutions, but didn't find any specific to this GraphQL implementation. Structurally, this looks like what I'm try to achieve, but it's a different platform altogether.
My questions:
is it possible to get this working (it seems like a pretty standard requirement to me)
if yes, how
if no, what's the limiting factor? (GraphQL, WPGraphQL, gatsby-source-wordpress)
🙏

Answer 1

I don't have your data structure and can't test. Does something like this work?
query MyQuery {
allWpCategory(
filter: {
posts: {
elemMatch: {
id: {
ne: "something"
}
}
}, {
id: {
in: ["dGVybTo0Mg=="]
}
}
})
{
nodes {
posts { // cannot filter here 🥲
nodes {
title
id
}
}
}
}
}