Strict enums from typescript types

[wcastand]

my use case is, i use gql.tada that generate types for my graphql api, but only generate types so i need to define the enum myself.

we use zod to define schema and validate our form, etc so i wanted to create an enum in zod that match and is validated by the enum from gql.tada.

code look like this:

export type Frequency = ReturnType<typeof graphql.scalar<"Frequency">> // Frequency = "IMMEDIATE" | "ONCE" | "DAILY" | "WEEKLY" | "MONTHLY"

export const zFrequency: z.ZodType<Frequency> = z.enum(["IMMEDIATE", "ONCE", "DAILY", "WEEKLY"])

but in it's case i get no error from typescript while it should because zod enum is missing MONTHLY.

I tried different lib and superstruct has Describe which is the equivalent of z.ZodType that manage to give me the proper error in

export const sFrequency: Describe<Frequency> = enums(["IMMEDIATE", "ONCE", "DAILY", "WEEKLY"])
/**
ERROR: 
[...]
Types of property 'schema' are incompatible.
    Property 'MONTHLY' is missing in type 
[...]
**/

was wondering if zod had an equivalent to Describe for a stricter match of enums?

EDIT:
just found a new issue exposing the same problem
#3534

[mdoury-oef]

The UnionToTuple type from type-fest cat be used to ensure the zod enum type matches the GraphQL type from gql.tada.

import { type UnionToTuple } from "type-fest"
import { type graphql } from "gql.tada"
import { z } from "zod"

type Scalar<TScalar extends Readonly<string>> = ReturnType<typeof graphql.scalar<TScalar>>

const FrequencySchema = z.enum<string, UnionToTuple<Scalar<"Frequency">>>(
  ["IMMEDIATE", "ONCE", "DAILY", "WEEKLY", "MONTHLY"]
) // ✅

const FrequencySchema = z.enum<string, UnionToTuple<Scalar<"Frequency">>>(
  ["IMMEDIATE", "ONCE", "DAILY", "WEEKLY"]
) // ❌

Error for missing members should look something like this:

 Argument of type '["IMMEDIATE", "ONCE", "DAILY", "WEEKLY"]' is not assignable to parameter of type '["IMMEDIATE", "ONCE", "DAILY", "WEEKLY", "MONTHLY"]'.

Caveat: the array order needs to match the union order.

[wcastand]

i switched to effect/schema but same issue, i solved it using this:

import { assert, type Equals } from "tsafe"
assert<Equals<(typeof TransactionCategory)[number], TransactionCategory>>()