Enums should support an omit method

[jasonkuhrt]

Example of what has to be done right now:

const a = z.nativeEnum( { a: 1, b: 2 } as const )
const b = z.nativeEnum( Remeda.omit( a._def.values, [ 'a' ] ) )

b._def.values.b // works
b._def.values.a
//            ^
// Property 'a' does not exist on type 'Omit<{ readonly a: 1; readonly b: 2; }, "a">'.

I'm not sure how to do it with zod enums actually.

This issue would be asking for native and zod enums though to support an omit method.

[JacobWeisenburger]

Here's how you do it with zod enums

const foo = z.enum( [ 'a', 'b' ] )

type ExcludeA = Exclude<z.infer<typeof foo>, 'a'>
// type ExcludeA = "b"

const bar = z.enum(
    foo.options.filter( x => x !== 'a' ) as [ ExcludeA, ...ExcludeA[] ]
)

bar.enum.b // works
bar.enum.a
//       ^
// Property 'a' does not exist on type 'Values<["b", ..."b"[]]>'.

[colinhacks]

There's an argument that this should be a top-level z.omit utility, which has been suggested elsewhere.

const a = z.nativeEnum( { a: 1, b: 2 } as const )
const omitted = z.omit(a, z.literal(2));

Once we have a ZodEmit schema type, we can add a global .omit method on the base ZodType.

[jasonkuhrt]

@colinhacks in your example you're omitting by value?

Once we have a ZodEmit schema type, we can add a global .omit method on the base ZodType.

How about generic static .omit function AND method helpers too?

[colinhacks]

you're omitting by value?

The inferred type of this this enum is 1 | 2 so you'd omit a literal 2 to remove that option.

const a = z.nativeEnum( { a: 1, b: 2 } as const )
// 1 | 2

You could also do this:

const a = z.nativeEnum({ a: 1, b: 2 } as const);
const omitted = z.omit(a, z.literal(a.values.b));

AND method helpers too?

Yep that's what I mean by "add the .omit method on the base ZodType". This would add the .omit method to all Zod schemas.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[jasonkuhrt]

Pleae re-open

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[jasonkuhrt]

Pleae re-open

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[jasonkuhrt]

Pleae re-open

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[jasonkuhrt]

Please re-open

[deriegle]

I was able to get this working using .refine. Of course it could be easier, but it was good enough for my solution.

Typescript Playground

import { z } from 'zod';

enum Status {
  todo = 'todo',
  inProgress = 'inProgress',
  completed = 'completed',
}

const notCompleted = z
  .nativeEnum(Status)
  .refine((status): status is Exclude<Status, Status.completed> => status !== Status.completed);

type NotCompleted = z.infer<typeof notCompleted>;
     // ^? type NotCompleted = Status.todo | Status.inProgress;

[colinhacks]

ZodEnum now has a .exclude() method that implements this behavior as of Zod 3.21.

Top level z.omit is probably not going to happen so I'm going to close.

[nullndr]

Would it be possible to add the .exclude() method also in ZodNativeEnum?

I have a case where I need to exclude from a prisma enum a specific value:

const validationSchema = z.object({
  ...
  type: z.nativeEnum(Prisma.AutomationType),
  ...
});

Currently I can recreate the native enum schema with a ZodEnum, and then call .exclude() on it, but my AutomationType would grow huge so I would like a simpler approach.