Invalid types generated

[borisovg]

The zod.ts file is generated with invalid types - we hit this when trying to use the package in our app but see (AI generated) repro (tested with graphql 6 and 7 packages) https://github.com/borisovg/zod-codegen-repro

pnpm repro
...
src/graphql.ts:65:3 - error TS2322: Type 'ZodObject<{ entered_options: ZodOptional<ZodNullable<ZodArray<ZodLazy<ZodNullable<ZodObject<Properties<EnteredOptionInput>, $strip>>>>>>; parent_sku: ZodOptional<...>; quantity: ZodNumber; selected_options: ZodOptional<...>; sku: ZodString; }, $strip>' is not assignable to type 'ZodObject<Properties<WishlistItemInput>, $strip>'.
  Type '{ entered_options: ZodOptional<ZodNullable<ZodArray<ZodLazy<ZodNullable<ZodObject<Properties<EnteredOptionInput>, $strip>>>>>>; parent_sku: ZodOptional<...>; quantity: ZodNumber; selected_options: ZodOptional<...>; sku: ZodString; }' is not assignable to type 'Properties<WishlistItemInput>'.
    The types of 'entered_options._input' are incompatible between these types.
      Type '({ uid: string | undefined; value: string | undefined; } | null)[] | null | undefined' is not assignable to type 'InputMaybe<InputMaybe<EnteredOptionInput>[]> | undefined'.
        Type '({ uid: string | undefined; value: string | undefined; } | null)[]' is not assignable to type 'InputMaybe<EnteredOptionInput>[]'.
          Type '{ uid: string | undefined; value: string | undefined; } | null' is not assignable to type 'InputMaybe<EnteredOptionInput>'.
            Type '{ uid: string | undefined; value: string | undefined; }' is not assignable to type 'InputMaybe<EnteredOptionInput>'.
              Types of property 'uid' are incompatible.
                Type 'string | undefined' is not assignable to type 'string'.
                  Type 'undefined' is not assignable to type 'string'.

65   return z.object({
     ~~~~~~

src/validation.ts:22:3 - error TS2322: Type 'ZodObject<{ entered_options: ZodOptional<ZodNullable<ZodArray<ZodLazy<ZodNullable<ZodObject<Properties<EnteredOptionInput>, $strip>>>>>>; parent_sku: ZodOptional<...>; quantity: ZodNumber; selected_options: ZodOptional<...>; sku: ZodString; }, $strip>' is not assignable to type 'ZodObject<Properties<WishlistItemInput>, $strip>'.
  Type '{ entered_options: ZodOptional<ZodNullable<ZodArray<ZodLazy<ZodNullable<ZodObject<Properties<EnteredOptionInput>, $strip>>>>>>; parent_sku: ZodOptional<...>; quantity: ZodNumber; selected_options: ZodOptional<...>; sku: ZodString; }' is not assignable to type 'Properties<WishlistItemInput>'.
    The types of 'entered_options._input' are incompatible between these types.
      Type '({ uid: string | undefined; value: string | undefined; } | null)[] | null | undefined' is not assignable to type 'InputMaybe<InputMaybe<EnteredOptionInput>[]>'.
        Type '({ uid: string | undefined; value: string | undefined; } | null)[]' is not assignable to type 'InputMaybe<InputMaybe<EnteredOptionInput>[]>'.
          Type '{ uid: string | undefined; value: string | undefined; } | null' is not assignable to type 'InputMaybe<EnteredOptionInput>'.
            Type '{ uid: string | undefined; value: string | undefined; }' is not assignable to type 'InputMaybe<EnteredOptionInput>'.
              Types of property 'uid' are incompatible.
                Type 'string | undefined' is not assignable to type 'string'.
                  Type 'undefined' is not assignable to type 'string'.

22   return z.object({
     ~~~~~~


Found 2 errors in 2 files.

Errors  Files
     1  src/graphql.ts:65
     1  src/validation.ts:22

AI suggestion for alternative types - I tested the v4 version and it seems to work but 🤷‍♂️

For Zod v4 output, generate:

type Properties<T> = {
  [K in keyof T]-?: z.ZodType<T[K], T[K]>;
};

Why this is better:

* -? forces the shape to include every key (as z.object({...}) expects).
* Optionality/nullability is still controlled by .optional()/.nullish() wrappers per field.
* Input/output stay aligned to the GraphQL type for that property (T[K]), instead of globally widening input to | undefined.

If they need compatibility with other Zod signatures, a robust internal alias could be:

type ZodSchemaFor<T> = z.ZodType<T, T>;
type Properties<T> = { [K in keyof T]-?: ZodSchemaFor<T[K]> };

(Or the v3-compatible 3-generic form if they support it in the same template.)