Date type handling?

This lib looks like a really nice approach. I don’t see support for Date types, though. Do you have a plan to support them?

[colinhacks]

Hey Joe,

So you want to be able to pass in, say, an ISO string to a Date field and have .parse return a proper Date object in its place?

const Person = z.object({
  createdAt: z.date()
})

const person = Person.parse({
  createdAt: `2020-04-09T22:11:52.520Z`
}) // passes

person.createdAt // Date object

I’m trying to keep this library from becoming a casting library, since casting is generally messy and difficult, especially when you’re dealing with static types. Currently the above code wouldn’t pass static validation, sincezod expects Person.createdAt to be a Date. To get it to work, I’d have to create a variant of the inferred schema type that changes all Date fields to Date | string, to accommodate the loosened restrictions on the input to .parse. Over time these “loosenings” would get messier and less intuitive.

I’d rather implement this is a refinement string type:

const Person = z.object({
  createdAt: z.string().refine({ is: 'isoString' });
})

I’m already planning to implement other built-in refinement validators ({ is: 'email' }, { is: 'url' }, etc.).

This way you could parse your schema, then be confident that passing Person.createdAt into Date.parse will return a valid date. Would that work for you?

[maneetgoyal]

Great 😃