Get schema with n-deep wrapper type stack

Question

I'm getting data from a database through GraphQL. There are two types: Group and Person. Groups have a field people which is a list of Person objects.

I'm trying to get a schema from the server using GraphQL's built-in introspection. The problem I have is that the people field is a non-nullable type wrapping a list-type wrapping a non-nullable type, and I have to use this wordy query:

{
    __type(name: "Group") {
        name
        fields {
            name
            type {
                name
                kind
                ofType {
                    kind
                    name
                    ofType {
                        kind
                        name
                        ofType {
                            kind
                            name
                            ofType {
                                kind
                                name
                            }
                        }
                    }
                }
            }
        }
    }
}

To get this schema:

{
    "data": {
        "__type": {
            "name": "Group",
            "fields": [
                {
                    "name": "people",
                    "type": {
                        "name": null,
                        "kind": "NON_NULL",
                        "ofType": {
                            "kind": "LIST",
                            "name": null,
                            "ofType": {
                                "kind": "NON_NULL",
                                "name": null,
                                "ofType": {
                                    "kind": "OBJECT",
                                    "name": "Person",
                                    "ofType": null
                                }
                            }
                        }
                    }
                }
            ]
        }
    }
}

In addition to being an inconvenient and difficult to read query, it's not generic, and I would have to know the max-depth of wrapper types in a schema to construct it.

Is there any way to get all wrapper types, regardless of depth, in a schema?

score 1 · Accepted Answer · answered May 08 '20 at 15:56

1

Unfortunately, there is no way to do that generically. There is no max depth because GraphQL supports wrapping a type with a List an arbitrary amount of times. So while commonly you will only see

[String!]!

this is also a valid type

[[[[[[[[[[[[String]!]!]!]!]!]!]!]!]!]!]!]!

You pretty much have to pick a reasonable depth and roll with it. For what it's worth, this is what the official "complete" introspection query looks like. It has a depth of seven.

answered May 08 '20 at 15:56

Daniel Rearden

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1

That said, you can turn an introspection result [into a GraphQLSchema object](https://github.com/graphql/graphql-js/blob/master/src/utilities/buildClientSchema.js) and work with that instead if you want an easier way of parsing types, field, etc. – Daniel Rearden May 08 '20 at 15:58

Get schema with n-deep wrapper type stack

1 Answers1