Cascade - Graphql

Documentation
1

@cascade is available as a directive which can be applied on fields. With the @cascade directive, nodes that don’t have all fields specified in the query are removed. This can be useful in cases where some filter was applied and some nodes might not have all listed fields.

For example, the query below would only return the authors which have both reputation and posts and where posts have text. Note that @cascade trickles down so it would automatically be applied at the posts level as well if its applied at the queryAuthor level.

{
    queryAuthor @cascade {
        reputation
        posts {
            text
        }
    }
}

@cascade can also be used at nested levels, so the query below would return all authors but only those posts which have both text and id.

{
    queryAuthor  {
        reputation
        posts @cascade {
            id
            text
        }
    }
}
This is a companion discussion topic for the original entry at https://dgraph.io/docs/graphql/queries/cascade/