Nexus resolve() returns PrismaPromise but gives error

Question

I am trying to build an apollo server with Nexus.js, Prisma and Typescript for a to-do app.

I created the Todo nexus type, and I wanted to create the query, but I'm having an error.
The definition:

import { extendType, objectType } from "nexus";

export const Todo = objectType({
  name: "Todo",
  definition(t) {
    t.id("id");
    t.nonNull.string("title");
    t.string("detail");
  },
});

export const TodoQuery = extendType({
  type: "Query",
  definition(t) {
    t.list.field("todos", {
      type: "Todo",
      resolve(_root, _args, ctx) {
        return ctx.db.todo.findMany(); // db is an instance of PrismaClient()
      },
    });
  },
});

The error:

Type '(_root: {}, _args: {}, ctx: Context) => PrismaPromise<Todo[]>' is not assignable to type 'FieldResolver<"Query", "todos">'.
  Type 'PrismaPromise<Todo[]>' is not assignable to type 'MaybePromise<({ detail?: string | null | undefined; id?: string | null | undefined; title: string; } | null)[] | null>'.
    Type 'PrismaPromise<Todo[]>' is not assignable to type 'PromiseLike<({ detail?: string | null | undefined; id?: string | null | undefined; title: string; } | null)[] | null>'.
      Types of property 'then' are incompatible.
        Type '<TResult1 = Todo[], TResult2 = never>(onfulfilled?: ((value: Todo[]) => TResult1 | PromiseLike<TResult1>) | null | undefined, onrejected?: ((reason: any) => TResult2 | PromiseLike<...>) | null | undefined) => Promise<...>' is not assignable to type '<TResult1 = ({ detail?: string | null | undefined; id?: string | null | undefined; title: string; } | null)[] | null, TResult2 = never>(onfulfilled?: ((value: ({ detail?: string | null | undefined; id?: string | null | undefined; title: string; } | null)[] | null) => TResult1 | PromiseLike<...>) | null | undefined, ...'.
          Types of parameters 'onfulfilled' and 'onfulfilled' are incompatible.
            Types of parameters 'value' and 'value' are incompatible.
              Type 'Todo[]' is not assignable to type '({ detail?: string | null | undefined; id?: string | null | undefined; title: string; } | null)[]'.
                Type 'Todo' is not assignable to type '{ detail?: string | null | undefined; id?: string | null | undefined; title: string; }'.
                  Types of property 'id' are incompatible.
                    Type 'number' is not assignable to type 'string'.

Answer 1

ID types in GraphQL are handled as String.
Probably, you are using number as the ID of the todo, so the type does not match, resulting in an error.

const SpecifiedScalars = {
  ID: 'string',
  String: 'string',
  Float: 'number',
  Int: 'number',
  Boolean: 'boolean',
}

from https://github.com/graphql-nexus/nexus/blob/11d028277e7fec241246237dbe31707c037407ee/src/typegenPrinter.ts#L44