Generated defaults for enums type results in typescript errors - wrong type

[VilleViktor]

Bug description

When generating schemas with enum that has default values, typescript errors occurs:

No overload matches this call.
  Overload 1 of 2, '(def: MyEnum): ZodDefault<ZodEnum<typeof MyEnum>>', gave the following error.
    Argument of type '"THREE"' is not assignable to parameter of type 'MyEnum'.
  Overload 2 of 2, '(def: () => MyEnum): ZodDefault<ZodEnum<typeof MyEnum>>', gave the following error.
    Argument of type 'string' is not assignable to parameter of type '() => MyEnum'.ts(2769)

8   myEnum: myEnumSchema.default('THREE')
                                 ~~~~~~~

Input

enum MyEnum {
    One = 'ONE',
    Three = 'Three'
 }

interface MyType {
  /**
   * @default THREE
   */
   myEnum: MyEnum
 }

Expected output

// Generated by ts-to-zod
import { z } from 'zod'
import { MyEnum } from './test'

export const myEnumSchema = z.enum(MyEnum)

export const myTypeSchema = z.object({
  myEnum: myEnumSchema.default(MyEnum.Three)
})

Actual output

// Generated by ts-to-zod
import { z } from 'zod'
import { MyEnum } from './test'

export const myEnumSchema = z.enum(MyEnum)

export const myTypeSchema = z.object({
  myEnum: myEnumSchema.default('THREE')
})

Versions

• "typescript": "~5.9.2",
• "zod": "^4.1.5"
• "ts-to-zod": "^4.0.0",

[fabien0102]

The problem is about * @default THREE, we have no way to match this value, can you try * @default myEnum.Three? (I think this will become a string anyway, I didn’t really think about this usecase)

[thomas-hanna-deel]

We came across the same issue. The enum values are available on the schema from zod so a proposed improvement could be something like this?

Input:

enum MyEnum {
    One = 'ONE',
    Three = 'Three'
 }

interface MyType {
  /**
   * @defaultEnum Three
   */
   myEnum: MyEnum
 }

Output:

// Generated by ts-to-zod
import { z } from 'zod'
import { MyEnum } from './test'

export const myEnumSchema = z.enum(MyEnum)

export const myTypeSchema = z.object({
  myEnum: myEnumSchema.default(myEnumSchema.enum.Three)
})

You don't get type safety on the JSdoc definition but the output will show a TS error if you pick an enum which isn't available.

Edit:
Had more of a look into this, if the parent enum schema has other methods called on it you need to unwrap the schema, possibly multiple times:

Output:

export const myEnumSchema = z.enum(MyEnum).optional().nullable();

export const myTypeSchema = z.object({
    myEnum: myEnumSchema.default(myEnumSchema.unwrap().unwrap().enum.Three),
});

[thomas-hanna-deel]

I came up with a simple solution for now which is to use a find and replace on the zod output to match against

.enum(MyEnum)

and replace with

.enum(Object.values(MyEnum) as `${MyEnum}`[])

This allows string literals of the values to be used for setting the .default()