GraphQL Schema

A brief look at how the data is modeled in this app.

Entities#

Book#

Field	Type
id	GraphQLID
name	GraphQLString
genre	GraphQLString
author	Author

Author#

Field	Type
id	GraphQLID
name	GraphQLString
age	GraphQLString
books	GraphQLList(Book)

You can find the schema declaration here. This is an example on how it looks like:

const BookType = new GraphQLObjectType({
    name: 'Book',
    fields: () => ({
        id: { type: GraphQLID },
        name: { type: GraphQLString },
        genre: { type: GraphQLString },
        author: {
            type: AuthorType,
            resolve(parent, args) {
                // MongoDB query
            }
        },
    }),
});

You probably wondering why fields is defined as a function instead of a simple object. This is because when we declare a schema that depends on another entity - in this case a book needs an author - if we set the field author with a AuthorType as its type and this schema declaration comes before the Author declaration, AuthorType will be undefined at this moment. When we pass a function instead, this is only called on execution time, when both entities are already declared.

For more information on how to set up a GraphQL schema and what are the GraphQL types, check their official docs