union of intersections doesn't work

Here’re types definitions:

import * as t from './superstruct'

const TOrderCreated = t.object({
    id: t.string(),
    sku: t.string(),
    quantity: t.number(),
})

export const TOrderChanged = t.object({
    id: t.string(),
    quantity: t.number(),
})

const TOrderCanceled = t.object({
    id: t.string(),
})

const TOrderEvent = t.union([
    t.intersection([t.type({_type: t.literal('created')}), TOrderCreated]),
    t.intersection([t.type({_type: t.literal('changed')}), TOrderChanged]),
    t.intersection([t.type({_type: t.literal('canceled')}), TOrderCanceled]),
])

type OrderEvent = t.Infer<typeof TOrderEvent>

Clearly I’m using _type as discriminator field, but I don’t want to mix it with the “payload” - specific events. Hence I’m doing intersection for adding discriminator field.

I would expect this to work properly:

let event: OrderEvent = t.create({ _type: 'changed', id: 'id123', quantity: 123 }, TOrderEvent)

However I get error:

StructError: Expected the value to satisfy a union of `intersection | intersection | intersection`, but received: [object Object]

[birtles]

@birtles that’s awesome! If you were interested in PR’ing I’d be open to it.

Thanks! Sure, it will take a bit of work to get it fully ready but I’ll try to get to it in the coming weeks.

[ianstormtaylor]

@birtles that’s awesome! If you were interested in PR’ing I’d be open to it.