Switch programmatically a property nullish or optional to required in Zod

Question

I'm working with objects in Zod. Let's say I have a base schema.

const baseSchema = z.object({
  id: z.string(),
  date: z.string().pipe(z.coerce.date()).optional(),
  free: z.boolean().optional(),
  paymentMethod: z.string().optional(),
  // many more properties below...
});

Now I need to define a second zod object based on the first one, but changing its properties. For example switch some optional to nullish (and viceversa), or switch a field optional/nullish to required.

What I don't want is to copy the entire object and paste it into a new zod schema and change manually every single property I need.

Is there any way I could do this with an inheritance behaviour in which I could modify certain properties from the base schema?

Answer 1

Yes you can, by using the .extend() method of zod, let's see how:

This is your baseChema.

const baseSchema = z.object({
  id: z.string(),
  date: z.string().pipe(z.coerce.date()).optional(),
  free: z.boolean().optional(),
  paymentMethod: z.string().optional(),
});

And now, this is the extended one, inheriting properties when you don't write them, and modifying the ones you specified:

const newSchema = baseSchema.extend({
  date: z.string().pipe(z.coerce.date()).nullable(), 
  paymentMethod: z.string().required()
});

You can also check other methods like pick() or omit().