arktype•16mo ago

Automatically applying parse.integer

Let's say I have a type I'm using to validate some API, e.g.

const personSchema = type({
    name:'string',
    age:'0<=number<=120'
})

const personSchema = type({
    name:'string',
    age:'0<=number<=120'
})

At some point, I also want to use this type to validate form input. As it's formData,the age will be a string not a number.

I know I can do something like this:

const formDataParser=type('parse.formData')
const coerce=type({'age?':'parse.integer'})
const parsedFormInput = formDataParser(formInput).pipe(coerce).pipe(personSchema)

const formDataParser=type('parse.formData')
const coerce=type({'age?':'parse.integer'})
const parsedFormInput = formDataParser(formInput).pipe(coerce).pipe(personSchema)

However, is there a way to somehow automate the coerce step? I have lots of these types (some of them dynamically created) and I'd rather avoid having to manually create an extra type to pick out the numeric fields and parse.integer them.

Maybe there's some way I can automatically pick out the number properties from a type and automatically build the coerce step so that parse.integer is only applied to any properties that are numeric in the final schema?

I'm fairly new to this, so it could just be my lack of Typescript skill. Any pointers would be much appreciated.

ssalbdivad•8/23/24, 9:31 AM

Sounds doable but definitely a bit tricky. There's no built-in "coerce" yet. I'd have to think about what the semantics of that would be relative to the existing parse keywords.

Where does personSchema come from? Could that be defined in a way where the parsing happens there, and the output could be extracted separately?

ssalbdivad•8/23/24, 9:32 AM

If you already have the personSchema type to compare with the form input, I guess you could iterate over the keys that way to see which should be converted to numbers

Stuart BOP•8/23/24, 9:43 AM

I'd assumed 'parse.integer' would convert a string to an integer and leave an integer alone, but if fails if the input is already an integer. Would there be a problem with having parse.integer just pass through the existing value if it's already an integer?

The personSchema is just a simple example. I have a whole bunch of data objects that can be written to a db, both via an API (where numerics will already be numbers) and forms (where the numerics will be strings).

I've built a simple form validator, to which I pass the formData and the arktype type. The validator function uses the passed type to validate the input and passes back the original data and a success message or errors.

I can always deal with this by creating 2 types instead of 1. One is the "API" type and the other one is a parse.integer for the numeric fields and piped to the API type. It just felt a little redundant. Feels like there should be a more elegant way.

ssalbdivad•8/23/24, 9:44 AM

I don't think I would ever make morphs accept their output types in general just because it's sometimes convenient

ssalbdivad•8/23/24, 9:44 AM

But I might add some additional keywords to help with that

ssalbdivad•8/23/24, 9:44 AM

e.g. there is a lift array that converts something to an array if it is not one already so it would be somewhat similar to that

ssalbdivad•8/23/24, 9:45 AM

I'm sure the right abstractions could help but it's important to strike a balance and not start implementing magical transformations with lots of edge cases as built ins. Ideally they should primarily be simple I/O

ssalbdivad•8/23/24, 9:46 AM

I think if I were going to add something like this though it would probably be like

Stuart BOP•8/23/24, 9:53 AM

Thanks David.
In the meantime, if I already have a type() defined, is there any way I can extract the keys of numeric properties from that type? I could then use them to build my parse.integer step.

SStuart B Thanks David. In the meantime, if I already have a type() defined, is there an...

ssalbdivad•8/23/24, 10:06 AM

A bit tricky to do, especially if you don't know the runtime type system but this seems to wrok

Stuart BOP•8/23/24, 10:14 AM

Thanks! And having read that, there's also the added bonus that I no longer feel dumb for not knowing how to do it myself

SStuart B Thanks! And having read that, there's also the added bonus that I no longer fee...

ssalbdivad•8/23/24, 10:14 AM

Yeah like I said definitely not the most trivial thing either at a type-level or at runtime haha

SStuart B I'd assumed 'parse.integer' would convert a string to an integer and leave an in...

PIat•9/4/24, 10:41 PM

I have the same use case

PIat•9/4/24, 10:42 PM

I would like to achieve such behavior

PPIat I would like to achieve such behavior

ssalbdivad•9/4/24, 10:43 PM

Can't you just write a morph?

PIat•9/4/24, 10:44 PM

Ooooh, you updated docs!

ssalbdivad•9/4/24, 10:45 PM

I added a few new sections. I also have some good abstractions for showing multiple definition types

Sssalbdivad Can't you just write a morph?

PIat•9/4/24, 10:45 PM

Oh righttttttt.... So this forum is about doing it inherently

PIat•9/4/24, 10:45 PM

Sorry

PPIat Sorry 🙈

ssalbdivad•9/4/24, 10:46 PM

Yeah, youc ould always just write

ssalbdivad•9/4/24, 10:46 PM

Which I think is a lot clearer anyways

Sssalbdivad Yeah, youc ould always just write `number.integer|string.parse.integer`

PIat•9/4/24, 10:46 PM

You could?????

ssalbdivad•9/4/24, 10:46 PM

Why not?

PIat•9/4/24, 10:47 PM

I never saw the being used in this way, it never even came across my mind

PIat•9/4/24, 10:47 PM

Just assumed it wouldn't work

ssalbdivad•9/4/24, 10:47 PM

Oh I guess I wrote it wrong haa

ssalbdivad•9/4/24, 10:47 PM

It should have been

PIat•9/4/24, 10:47 PM

Because it seems so complicated to implement

ssalbdivad•9/4/24, 10:48 PM

What part? It's all just composable rules in the type system

PIat•9/4/24, 10:48 PM

Hehe...

PIat•9/4/24, 10:48 PM

The DX is just too good to be true

Sssalbdivad What part? It's all just composable rules in the type system

PIat•9/4/24, 10:48 PM

I love it

PPIat I would like to achieve such behavior

ssalbdivad•9/4/24, 10:49 PM

A conform adapter would actually be really useful I know a couple teams that use conform that are interested in ArkType

PIat•9/4/24, 10:49 PM

I am in the process of making one

ssalbdivad•9/4/24, 10:49 PM

So I see, really excited to see that! Happy to do a review once it's ready

PIat•9/4/24, 10:50 PM

It works with the strings, now just to add morphs

PIat•9/4/24, 10:51 PM

I'm thinking whether creating an exported would be the best way...

PIat•9/4/24, 10:52 PM

The scope would then be extended and have all the necessary keys

ssalbdivad•9/4/24, 10:52 PM

Definitely an option. Most things you can do with or without a scope so it comes down to preference.

ssalbdivad•9/4/24, 10:53 PM

Scopes let you use the string syntax more with your own keywords and there's a couple things they let you do that would otherwise not be possible:

Configuring sets of types at once
Representing cyclic types

Outside that though it is down to preference really

PPIat I would like to achieve such behavior

PIat•9/4/24, 10:53 PM

Because with Zod it's kind of simple to override the behaviour. Because it's not composable in the same way, the library authors can simply predict what the users might want

PIat•9/4/24, 10:54 PM

But Arktype allows for many crazy things to happen

ssalbdivad•9/4/24, 10:54 PM

You can just accept an option for or whatever Zod does right?

Sssalbdivad Scopes let you use the string syntax more with your own keywords and there's a c...

PIat•9/4/24, 10:54 PM

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