A partly partial with io-ts

[midzdotdev]

I just posted a new question on StackOverflow regarding making a partial from an existing schema.

Any help would be appreciated.

---

I'm having some issues with using io-ts. I've found that its really lacking documentation, most of the progress I've made is through GitHub issues. And no I don't understand the HKTs so no help there.

Basically I'm creating a type elsewhere, type which has a certain set of keys:

import * as S from 'io-ts/lib/Schema'

const someType = S.make(S => S.type({
  id: S.string,
  foo: S.string,
  bar: S.boolean
}))

type T = S.TypeOf<typeof someType>

And I need to transform this to a partial where some keys are still required. Say just the id key is still required, defining the type in TS would be like:

type PartlyPartial <T> = Partial<T> & { id: string }

Simple!

Now, I want to be able to do this at runtime through io-ts so that I can create a validator function with the Guard module. This is what I've got so far:

import * as G from 'io-ts/lib/Guard'

const propsBase = S.make(S => S.type({
  id: S.string
}))

const partial = S.make(S => S.intersection(
  someType(S) // needs to be partial,
  propsBase(S)
))

// So that this returns `true`
partial(G.guard).is({
  id: 'some id',
  bar: true
})

But the someType(S) defines the type as having all keys required, but none of them should be required.

[gcanti]

making a partial from an existing schema

That's not possible

[midzdotdev]

I appreciate you getting back to me.

Is there no workaround that I could create temporarily? All I need to do it validate with these conditions.

Could the properties be attached as a property to the Schema fn produced by make for future manipulation. I understand it seems you've tried to get away from the whole props idea after dealing with io-ts' initial Type but in my case it seems necessary.

[RemiLelaidier]

Found that
https://stackoverflow.com/questions/61311182/a-partly-partial-with-io-ts

[midzdotdev]

Found that
https://stackoverflow.com/questions/61311182/a-partly-partial-with-io-ts

Yes, that's my post which I linked at the beginning, although I didn't reply saying that I found a workaround.

If anybody has the same issue, then its possible to create a wrapper around make which provides the features I'm talking about.