Support @Resolver without type name or class (code first)

I’m submitting a…

[ ] Regression 
[x] Bug report
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead post your question on Stack Overflow.

Current behavior

Application throw the following error when using @Resolver() without specifying any type name or type class:

  TypeError: Cannot read property 'prototype' of undefined

Caused by: https://github.com/nestjs/graphql/blob/master/lib/decorators/resolvers.decorators.ts#L250

Expected behavior

No error should be thrown.

Minimal reproduction of the problem with instructions

Sorry for my poor english, here is a test case to reproduce the issue: https://github.com/zhenwenc/nest-graphql-issues/blob/master/test/resolver-without-type-name.spec.ts

Environment

Nest version: 6.0.0

[itskemo]

@zhenwenc I have happen to stumble upon the very same issue when using @ResolveProperty() decorator and what solved for me was to properly annotate the Resolver as per docs using Type not string name so for example in your case:

❌ @Resolver('SampleObject') ✅ @Resolver(of => SampleObject)

So in your test simply change the annotation as specified above and all should work as expected.

Hope it helps! Tom

[kamilmysliwiec]

Well, you’re right. Thanks for reminding me 😃