type-graphql: Cannot read property 'type' of undefined on building with union result type

I have an error when working with union result type. Here is working demo Uncomment getUserWithUnion method in resolver.ts to reproduce the problem.

TypeError: Cannot read property 'type' of undefined
    at /home/maxim/workspace/demo/node_modules/type-graphql/dist/schema/schema-generator.js:66:101
    at Array.map (<anonymous>)
    at types (/home/maxim/workspace/demo/node_modules/type-graphql/dist/schema/schema-generator.js:66:22)
    at resolveThunk (/home/maxim/workspace/demo/node_modules/graphql/type/definition.js:438:40)
    at defineTypes (/home/maxim/workspace/demo/node_modules/graphql/type/definition.js:837:15)
    at GraphQLUnionType.getTypes (/home/maxim/workspace/demo/node_modules/graphql/type/definition.js:806:26)
    at typeMapReducer (/home/maxim/workspace/demo/node_modules/graphql/type/schema.js:272:28)
    at typeMapReducer (/home/maxim/workspace/demo/node_modules/graphql/type/schema.js:286:20)
    at Array.reduce (<anonymous>)
    at new GraphQLSchema (/home/maxim/workspace/demo/node_modules/graphql/type/schema.js:145:28)

About this issue

Original URL
State: closed
Created 4 years ago
Comments: 16 (6 by maintainers)

Most upvoted comments

https://typegraphql.ml/docs/unions.html

types: () => [Movie, Actor], // function that returns array of object types classes

As stated per GraphQL specification, union type can consist only object types: http://graphql.org/learn/schema/#union-types

MichalLytek on Feb 10, 2020