[WIP] Support enums

[Weakky]

• Implements a proper TS/Flow parser to be able to make valuable comparisons between GraphQL and Model types.

• Support Enum as scalar values (GraphQL enums are always inlined in graphqlgen.ts)

• Support smart code generation/scaffolding:

Given the following GraphQL types:

type User {
  id: String!
  penColor: Color!
}

enum Color {
  RED
  GREEN
  BLUE
}

and the following model type:

type User {
  id: string
  penColor: ModelColor
}

the resolver for the penColor field will be generated as a defaultResolver if:

• ModelColor is a subset or has the same values as Color. That is to say if ModelColor is of type:
  • type ModelColor = 'RED'
  • type ModelColor = 'BLUE'
  • type ModelColor = 'GREEN'
  • type ModelColor = 'RED' | 'BLUE'
  • type ModelColor = 'RED' | 'GREEN'
  • type ModelColor = 'BLUE' | 'GREEN'
  • type ModelColor = 'RED' | 'BLUE' | 'GREEN' etc..

or if penColor is of type:

• penColor: 'RED'
• penColor: 'BLUE'
• penColor: 'GREEN'
• penColor: 'RED' | 'BLUE'
• penColor: 'RED' | 'GREEN'
• penColor: 'BLUE' | 'GREEN'
• penColor: 'RED' | 'BLUE' | 'GREEN' etc..

[schickling]

Any reason why () is needed here?

[Weakky]

The parenthesis aren't in the code generator. They must be added by prettier somehow 😕

[schickling]

I've released a first version which can be installed via graphqlgen@beta. Please report if you run into any problems 🙏