Correct way to infer error schema for form data

[gregbrowndev]

Hi,

Thanks for the work on this project!

I'm struggling to understand how to work with the errors from useFormData schema. I want to validate a FormData object using Zod, but have a structured way to return the fieldErrors and formErrors that you'd natively get with Zod.

However, it seems that the errors the schema creates from useFormData and .error.flatten() isn't assignable to the usual Zod errors type that can be defined with z.inferFlattenedErrors

Example

import { z } from 'zod';
import { zu } from 'zod_utilz';

const schema = z.object({
  foo: z.string(),
  bar: z.number(),
});

const formSchema = zu.useFormData(schema);

const formData = new FormData();
formData.append('foo', 'hello');
formData.append('bar', '123');

const result = formSchema.safeParse(formData);

if (result.error) {
  const errors = result.error.flatten();

  // errors: z.typeToFlattenedError<FormData | URLSearchParams, string>
  // can't be assigned to z.inferFlattenedErrors<typeof formSchema>
  // or even z.inferFlattenedErrors<typeof schema>

  // errors.fieldErrors has this type:
  // fieldErrors: {
  //   [Symbol.iterator]?: string[] | undefined;
  //   keys?: string[] | undefined;
  //   toString?: string[] | undefined;
  //   sort?: string[] | undefined;
  //   forEach?: string[] | undefined;
  //   entries?: string[] | undefined;
  //   ... 7 more ...;
  //   size?: string[] | undefined;
  // }
}

[JacobWeisenburger]

What version of zod are you using?