Iterate Over Custom Directives in GraphQL Schema

0
votes

I have a simplified schema.graphql file with one type and one custom directive (at the field and object level). In Typescript, how can I programmatically get the type and type directive, and iterate over the fields and field directives?

type Test @myCustomDirective() {
  id: String! @myCustomDirective()
}

This post says "This is not currently supported by GraphQL":
Is there any way to read GraphQL Directives on a Type with Query Introspection?

And the GitHub issue says this feature is being considered:
https://github.com/graphql/graphql-spec/issues/300

Then how is AWS AppSync doing this? See below.

// The following keeps custom directives:
parse(schema); // Return type: graphql.DocumentNode

// The following removes custom directives:
buildSchema(schema); // Return type: GraphQLSchema
  1. AWS AppSync > Export Schema > Schema.json does include custom directives but is an AWS AppSync specific solution and is an expensive API operation.
aws appsync get-introspection-schema --api-id abc123 --format JSON --include-directives output.json

  1. I tried GraphQL Code Generator Introspection plugin. But it removes custom directives from types and fields.

    https://www.graphql-code-generator.com/plugins/introspection

  2. I tried graphql/utilities but it also removes custom directives from types and fields.

graphql.introspectionFromSchema(graphqlSchema)

// or

graphql.graphqlSync({ schema: graphqlSchema, source: graphql.getIntrospectionQuery() }).data as unknown as graphql.IntrospectionQuery;

https://graphql.org/graphql-js/utilities/

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