Make .parse an assertion function

const Post = z.object({slug: z.string()})

const thing = JSON.parse('{"slug": "hi"}')
// thing is any
Post.parse(thing)
// thing is {slug: string}

I realize that I could do const thing = Post.parse(JSON.parse(...)) or make a second variable, but I don’t really want to do that. My use case is in Remix.

Here’s what I have to do now:

const data = LoaderData.parse(useLoaderData())

But some people are freaked out when they see me passing a hook call in an arguments list. So I’d prefer to be able to do this:

const data = useLoaderData()
LoaderData.parse(data)

But currently that leaves data as any.

[kentcdodds]

Hey @scotttrinh,

Thanks for the kind words! I’m glad I’ve been helpful to you 😃

If this were just for my own apps then a custom hook would be fine, but I’m thinking about using this in official Remix docs and we want to have something that feels nicer than telling people to make their own hook. Something you can add without much work.

I think an assertInput method would be perfect. I’ve never heard of preprocess, but I think I would prefer that preprocess is ignored for the assertInput if possible.

[kentcdodds]

Having a separate function that applies the preprocess is fine for my use case 👍