Return ENUM - Cannot return null for non-nullable field

Question

I am using apollo-server-lambda, Prisma ORM and graphql-codegen.

I have a query (getBookById) that returns a Book. Book contains an enum called BookStatus. I want to be able to return in ENUM in the playground but I get the error:

Cannot return null for non-nullable field Book.bookStatus.

BookStatus - TypeDef

enum BookStatus {
  OPEN
  DRAFT
  CLOSED
}

Book - TypeDef

type Book {
  id: ID!
  title: String!
  bookStatus: BookStatus!
}

getBookById - TypeDef

type Query {
  getBookById(getBookByIdInput: GetBookByIdInput): Book
}

Answer 1

SOLVED:

The issue was that I was using Prisma as ORM. When I was getting a new book, I was writing the code:

  const foundBook = await prisma.book.findUnique({
    where: {
      id: bookId
    }
  });

The issue is that the book was created using this code:

  const newBook = await prisma.book.create({
    data: {
      user_id: userId,
      title: title,
      author: author,
      publication_year: publicationYear,
      isbn: isbn,
      photos: photos,
      book_condition: bookCondition,
      exchange_yype: exchangeType,
      book_status: bookStatus,
    },
  });
      
  return newBook;

};

The mix of snake_case and camelCase created the issue. Once everything was camelCase, the problem got solved.