TypeError: Cannot convert undefined or null to object

[DanielKucal]

I have seen those similar issues nestjs/nest#484, nestjs/nest#488 and they seem to be resolved. However, I am on @nestjs/graphql v3.0.0, @nestjs/common and /core v5.0.0 and the following code:

@Module({
	imports: [GraphQLModule]
})
export class GraphQLSetupModule {
	private readonly schema: any;

	constructor(graphQLFactory: GraphQLFactory) {
		this.schema = graphQLFactory.createSchema({
			typeDefs: mergedTypes
		});
	}
}

where mergedTypes is exactly:

schema {
  query: Query
}

type Query {
  countries: [Country]
}

directive @entity on OBJECT

type Country @entity {
  # The id is also the official ISO code of the country.
  _id: ID
  name: String
}

fails with stack trace:

TypeError: Cannot convert undefined or null to object
    at Function.getPrototypeOf (<anonymous>)
    at ResolversExplorerService.filterResolvers (/Users/danielkucal/Applications/someApp/src/node_modules/@nestjs/graphql/dist/resolvers-explorer.service.js:34:34)
    at resolvers.flatMap.instance (/Users/danielkucal/Applications/someApp/src/node_modules/@nestjs/graphql/dist/resolvers-explorer.service.js:27:66)
    at map (/Users/danielkucal/Applications/someApp/src/node_modules/@nestjs/graphql/dist/resolvers-explorer.service.js:31:102)
    at Array.map (<anonymous>)
    at lodash_1.flattenDeep.modules.map.module (/Users/danielkucal/Applications/someApp/src/node_modules/@nestjs/graphql/dist/resolvers-explorer.service.js:31:80)
    at Array.map (<anonymous>)
    at ResolversExplorerService.flatMap (/Users/danielkucal/Applications/someApp/src/node_modules/@nestjs/graphql/dist/resolvers-explorer.service.js:31:45)
    at ResolversExplorerService.explore (/Users/danielkucal/Applications/someApp/src/node_modules/@nestjs/graphql/dist/resolvers-explorer.service.js:27:32)
    at GraphQLFactory.createSchema (/Users/danielkucal/Applications/someApp/src/node_modules/@nestjs/graphql/dist/graphql.factory.js:23:149)
    at new GraphQLSetupModule (/Users/danielkucal/Applications/someApp/src/LHBackend/dist/src/graphql/GraphQLSetupModule.js:27:38)
    at resolveConstructorParams (/Users/danielkucal/Applications/someApp/src/node_modules/@nestjs/core/injector/injector.js:64:84)
    at Injector.resolveConstructorParams (/Users/danielkucal/Applications/someApp/src/node_modules/@nestjs/core/injector/injector.js:86:30)
    at process._tickCallback (internal/process/next_tick.js:178:7)

Any ideas? Thanks in advance!

[cschroeter]

Works for me. Can you provide an example repo?

[DanielKucal]

Further debugging shows it's probably caused by not-yet resolved dependency... It uses a resolver which returns a Promise and the error pasted here occurs before and Promise is resolved and instance of that service (for RabbitMQ) is null. It doesn't occur on other developer's Windows machine. Can I know what OS do you use? Maybe there is a relation.

[DanielKucal]

The problem in our application was that GraphQL schema creation had been placed in a constructor of module instead of configure() lifecycle method. It was working on Windows and Linux, yet not on MacOS.

[lock]

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