GraphQL- conditionally determine the type of a field in a schema - graphql

Question

I have the following mongoose schema:
const MessageSchema = new Schema({
author: {
account:{
type:String,
enum:['employee','admin'],
},
id: String,
}
//other fields
})
Then in my graphql-schemas file, I have the following schema types:
const MessageType = new GraphQLObjectType({
name: 'Message',
fields: () => ({
account: {
type: AuthorType,
//resolve method
},
id: {type: GraphQLString},
})
})
const AuthorType= new GraphQLObjectType({
name: 'Author',
fields: () => ({
account: {
type://This will either be AdminType or EmployeeType depending on the value of account in db (employee or admin),
//resolve method code goes here
}
})
})
As indicated in the comments of AuthorType, I need the account field to resolve to Admin or Employee depending on the value of the account field in the database.
How do I conditionally determine the type of a field in a schema on the fly?

Answer 1

Instead of determining the type on the fly, I restructured my code as shown below:
const MessageType = new GraphQLObjectType({
name: 'Message',
fields: () => ({
id:{type:GraphQLString},
author: {
type: AuthorType,
async resolve(parent, args) {
if (parent.author.account === 'guard') {
return await queries.findEmployeeByEmployeeId(parent.author.id).then(guard => {
return {
username: `${guard.first_name} ${guard.last_name}`,
profile_picture: guard.profile_picture
}
})
} else if (parent.author.account === 'admin') {
return {
username: 'Administrator',
profile_picture: 'default.jpg'
}
}
}
},
//other fields
})
})
const AuthorType = new GraphQLObjectType({
name: 'Author',
fields: () => ({
username: {type: GraphQLString},
profile_picture: {type: GraphQLString},
})
})
Since all I need from the AuthorType is the author's username and profile picture, both employee and administrator have these fields, which I pass to AuthorType.
In MessageType, I apply the logic to determine account type in the resolve method of author, then construct custom object out of the logic, to match AuthorType.