How to create a custom mutation Output with Prisma fields

[baconcheese113]

I'd like to create a mutation Output type composed of a prismaField and a string, something like:

builder.mutationFields((t) => ({
  getUserAndToken: t.object({
    type: (t) => ({
      user: t.prismaField({ type: 'User' }),
      token: t.string(),
    }),
    args: {
      email: t.arg.string({ required: true }),
      password: t.arg.string({ required: true }),
    },
    resolve: async (_root, args, { prisma, user }) => {
      return { user, token: 'myToken' };
    },
  }),
});

This type would only be used for this mutation return, is this possible?

[hayes]

I'd do something like this:

const User = builder.prismaObject('User', { ... });
const UserAndToken = builder.objectRef<{ token: string, user: User }>('UserAndToken').implement({
  fields: t => ({
    user: t.field({ type: User, resolve: (parent) => parent.user }),
});
builder.mutationFields((t) => ({
  getUserAndToken: t.field({
    type: UserAndToken,
    args: {
      email: t.arg.string({ required: true }),
      password: t.arg.string({ required: true }),
    },
    resolve: async (_root, args, context, info) => {
      // get a query object that includes selections nested inside UserAndToken.user
      const query = queryFromInfo({
        context,
        info,
        path: ['user'], 
      });
      
      const user = await context.prisma.user.findUniqueOrThrow({ ...query, where: { /* your lookup here */ } });
      return { user, token: 'myToken' };
    },
  }),
});

[baconcheese113]

Thanks @hayes, that worked great! Can you verify that the following is true?

It seems the generic parameter should reference your Prisma model type being returned, but the t.field() type should reference your Pothos schema type

import { User as UserModel } from '@prisma/client';
import { User } from '../graphTypes/userGraphType';

const UserAndToken = builder
  .objectRef<{ user: UserModel; token: string }>('UserAndToken')
  .implement({
    fields: (t) => ({
      user: t.field({ type: User, resolve: (root) => root.user }),
    }),
  });
```ts

[hayes]

Yup thats correct. Technically the generic type should reference whatever your User type expects as it's parent. By default this is the full Type from Prisma, but if you use select or include on the prismaObject, this can change the expected type