Loadable Node

[litewarp]

I am having trouble with the loadable node builder. Specifically, I am confused about how to use classes to get isTypeOf checking using the Node Builder. If I try and pass the class to the builder (like with objects), I get the error that Ref Class User { ... } has not been implemented. If I try it with just the string 'User', the node gets created, but if I query by id, it returns the Abstract type \"Node\" must resolve to an Object type at runtime for field \"Query.node\" error.

Is there something obvious I am doing wrong? How should I implement this?

export class User {
  id: string
  firstName: string
  lastName: string
  name: string
  email: string

  constructor(id: string, name: string, email: string, firstName: string, lastName: string) {
    this.id = id
    this.firstName = firstName
    this.lastName = lastName
    this.name = name
    this.email = email
  }
}

const UserNode = builder.loadableNode('User', {
  id: {
    resolve: (user) => user.id
  },
  isTypeOf: (obj: Record<string, unknown>) => obj instanceof User,
  fields: (t) => ({
    firstName: t.string({
      resolve: (src) => src.firstName
    }),
    lastName: t.string({
      resolve: (src) => src.lastName,
      nullable: true
    }),
    name: t.string({
      resolve: (src) => (src.lastName ? `${src.firstName} ${src.lastName}` : src.firstName)
    }),
    email: t.string({
      resolve: (src) => src.email
    }),
  }),
  load: async (ids: string[], context: ContextType): Promise<User[]> => {
    ...
  },
})

[hayes]

This is likely a bug. I'll try to fix it tonight

[litewarp]

That would be amazing. Thanks.

[hayes]

I've tried to reproduce this, but it seems like everything is working as intended. Can you add some console.logs into your isTypeOf handlers to see that it is being called, and that the check is returning true?

[litewarp]

Nevermind. I found the test example but it doesn't use classes.

Is there no auto-magic resolution with classes when using the node interface? It's fine if I have to manually write a resolveType function, but it changes how I'll structure the underlying data. For example, I'd have to either pull in labels from the database or make sure each model from the database has a property unique to the model.

Sorry to bug you with so many questions. I appreciate your responsiveness.

[litewarp]

Interesting. Sounds like an issue with the load function. Can you confirm it is actually loading class instances? Typescript let's you resolve objects of the right shape even if it's not actually an instance.

How would I figure out whether it's loading class instances?

[hayes]

You could save the return value as a variable and do an instance of check on one of the items in the returned list inside the load function. Hard to tell without knowing more about what the load function does.

[litewarp]

Ahh I think I get it and why it's not working as I intended.

My fetch function doesn't naturally return a class like Mongoose or TypeORM does. So I'd have to instantiate the class before returning it anyways.

Im not a big user of classes so in the past I'd just include a property on the returned fetch object that the isTypeOf resolver can check.

Thanks again for your help.

[litewarp]

This was the answer. Posting it as a separate comment so I can mark it as resolved.

[litewarp]

The answer for anyone looking is that your load function has to return a class instance. So if your fetch call does not do it automatically, you need to return the class -- i.e. return new User({ ...properties })