Interesting approach for using GraphQL with a graph database.
There is also an integration for Neo4j [1] that works similarly (it translates GraphQL to Cypher), however it also exposes Cypher in GraphQL through a @cypher directive, which maps complex graph traversals/aggregations to a single GraphQL field.
Primer on how to use it: https://blog.kensho.com/compiled-graphql-as-a-database-query...
I work at Kensho and we use it with queries that are 10+ levels of nesting with no problems.