Unable to pass z.ZodType as argument to merge

[agoose77]

Hi all,

Following the advice for circular references, I've built this schema for a table-of-contents in the sphinx-external-toc Python package:

import { z } from 'zod';

const TOCTreeOptions = z
  .object({
    caption: z.string(),
    hidden: z.boolean(),
    maxdepth: z.number(),
    numberted: z.boolean(),
    reversed: z.boolean(),
    titlesonly: z.boolean(),
  })
  .partial();

const FileEntry = z.object({
  file: z.string(),
  title: z.string().optional(),
});

const URLEntry = z.object({
  url: z.string(),
  title: z.string().optional(),
});

const GlobEntry = z.object({
  glob: z.string(),
});

/** Basic TOC Trees **/
type NoFormatSubtreeType = z.infer<typeof TOCTreeOptions> & {
  entries: z.infer<typeof NoFormatEntry>[];
};
const NoFormatSubtree: z.ZodType<NoFormatSubtreeType> = TOCTreeOptions.extend({
  entries: z.lazy(() => NoFormatEntry.array()),
});

type NoFormatShorthandSubtreeType = {
  entries: z.infer<typeof NoFormatEntry>[];
  options?: z.infer<typeof TOCTreeOptions>;
}
const NoFormatShorthandSubtree: z.ZodType<NoFormatShorthandSubtreeType> = z.object({
  entries: z.lazy(() => NoFormatEntry.array()),
  options: TOCTreeOptions.optional(),
});

const NoFormatHasSubtrees = z.object({
  subtrees: NoFormatSubtree.array(),
});

const NoFormatEntry = z.union([
  FileEntry.merge(NoFormatShorthandSubtree),
  FileEntry.merge(NoFormatHasSubtrees),
  FileEntry,
  URLEntry,
  GlobEntry,
]);

const NoFormatTOCBase = z.object({
  root: z.string(),
  defaults: TOCTreeOptions.optional(),
});

const NoFormatTOC = z.union([
  NoFormatTOCBase.merge(NoFormatShorthandSubtree).strict(),
  NoFormatTOCBase.merge(NoFormatHasSubtrees).strict(),
  NoFormatTOCBase.strict(),
]);

This fails on the calls to merge that pass NoFormatShorthandSubtree as an argument.

I can understand why this fails (ZodType isn't ZodObject), but is there a way to solve this using merge?

In my specific case, I can probably drop the strict requirement, and thus use and instead of merge, but it's not ideal!

[danielBorowik]

Hi, I stumbled upon similar issue too and managed to resolve it using satisfies operator.

import { z } from 'zod'

type TypeA = { name: string }
type TypeB = { surname: string }

const objectWithName: z.ZodType<TypeA> = z.object({
  name: z.string()
})

const objectWithSurname: z.ZodType<TypeB> = z.object({
  surname: z.string()
})

const merged = objectWithName.merge(objectWithSurname)

The code above throws TS2339: Property merge does not exist on type ZodType<TypeA, ZodTypeDef, TypeA>, but this:

import { z } from 'zod'

type TypeA = { name: string }
type TypeB = { surname: string }

const objectWithName = z.object({
  name: z.string()
}) satisfies z.ZodType<TypeA>

const objectWithSurname = z.object({
  surname: z.string()
}) satisfies z.ZodType<TypeB>

const merged = objectWithName.merge(objectWithSurname)

works fine. I hope it helps : )