Add option to use nativeEnum for Zod enums

[Arnagos]

Add option to use nativeEnum for Zod enums

Current behavior

Currently, generating enums to Zod schemas results in output like this:

export const Currency = zod.union([zod.literal(0), zod.literal(1)]);

export type Currency = zod.input<typeof Currency>;

This is useful for validation but not for development, where we would rather use the actual names defined in the source enum.

Generating the same object as a const results in this vastly more useful object for development:

export type Currency = (typeof Currency)[keyof typeof Currency];

export const Currency = {
  Chf: 0,
  Eur: 1
} as const;

Proposed behavior

It would be nice if we could have both at the same time.

Proposed solution

Luckily, Zod allows exactly that:

import { z as zod } from 'zod';

const CurrencyObject = {
  Chf: 0,
  Eur: 1
} as const;

export const CurrencySchema = zod.nativeEnum(CurrencyObject);

export const Currency = CurrencySchema.enum;

export type Currency = zod.input<typeof CurrencySchema>;

This way we can use the schema as CurrencySchema, and the named enum values as i.e. Currency.CHF