Prisma generate object fields options

[haleksandre]

Hi,

I've created a small Prisma generator that kind of mimick 'nexus-prisma' but for Pothos, As I like the mix between needing to explicitly declare your every needed objects, fields, etc in your schema but most of the underlying information is generated from the prisma schema. The only problem I'm currently facing is the typings which are pretty complexed. Not sure if it would be actually possible.

Here's an example of what the generator does.

The following schema

/// The user
model User {
  id        String  @id @default(cuid())
  email     String  @unique
  username  String  @unique
  /// The password
  password  String
}

Will generate the following TS

export const User = {
  $name: "User",
  $description: "The user",
  id: {
    name: "id",
    type: "ID",  // <-- These is what seems to cause the typing issue since type is typed as `string`
    description: undefined,
    nullable: false,
  },
  email: {
    name: "email",
    type: "String",
    description: undefined,
    nullable: false,
  },
  username: {
    name: "username",
    type: "String",
    description: undefined,
    nullable: false,
  },
  password: {
    name: "password",
    type: "String",
    description: "The password",
    nullable: false,
  },
}

Importing this generated TS into the Primsa object

import { builder } from './builder'
import { User } from './generated/user'

// Get typing errors as `type` is typed as `string` 
builder.prismaObject('User', {
  name: User.$name,
  description: User.$description,
  fields: (t) => ({
    id: t.expose('id', { ...User.id }),
    email: t.expose('email', { ...User.email }),
    username: t.expose('username', { ...User.username }),
    password: t.expose('password', { ...User.password })
  }),
});

The workaround for now is to explictly pass the type after the spread

// No typing errors as type overwrite the type `string` with the correct type
builder.prismaObject('User', {
  name: User.$name,
  description: User.$description,
  fields: (t) => ({
    id: t.expose('id', { ...User.id, type: "ID" }),
    email: t.expose('email', { ...User.email,  type: "String"  }),
    username: t.expose('username', { ...User.username, type: "String" }),
    password: t.expose('password', { ...User.password, type: "String" })
  }),
});

So the question is basically to know if it's possible to get the typing right without the need to apply the workaround for each field? If it is, is there an example of something similar so that I canget a better idea how to achieve this?

Thanks for your time, really appreciate!

[hayes]

If you have your generator add as const to your definitions that might fix your type issues without having to generate more complicated types

[haleksandre]

It works! Thansk a lot!

Here I was trying a bunch of complex type without success 😅

[haleksandre]

I stumbled upon a typing issue for lists

[field]: {
  // ...
  type: ["String"] as const
  // ...
}

Will result in a mutable typing issue like so

Type 'readonly ["String"]' is not assignable to type 'TypeParam<ExtendDefaultTypes<Schema>>'.
  The type 'readonly ["String"]' is 'readonly' and cannot be assigned to the mutable type '[OutputType<ExtendDefaultTypes<Schema>>]'

Any idea if it'll be possbile to type this without generating more complex type?

[hayes]

You can do ["String" as const]. I should fix this in Pothos though

[haleksandre]

I still get a typing issue if I do ["String" as const]

Type '"String"[]' is not assignable to type 'TypeParam<ExtendDefaultTypes<Schema>>'.
  Type '"String"[]' is not assignable to type '[OutputType<ExtendDefaultTypes<Schema>>]'.
    Target requires 1 element(s) but source may have fewer.

Looks like the problem is Typescript doesn't see ["String" as const] as a tuple but as an array a "String".

[haleksandre]

Looks like it is working if I do ["String"] as ["String"].

[field]: {
  //...
  type: ["String"] as ["String"],
  //...
}