Validation

valibot at the edge — how page.actions and route() validate input, and what the error shapes look like.

Schemas live in the feature's shared/schema.c so the server wrapper and the client form share one definition:

import * as v from 'valibot'

export createNoteSchema := v.object
	title: v.pipe v.string(), v.trim(), v.minLength(1, 'title is required')
	body: v.optional v.string(), ''

export type CreateNoteInput = v.InferOutput<typeof createNoteSchema>

valibot is a dependency of your app, not of norns; the starter installs it.

#`validate(schema, raw)`

The function both wrappers use. It accepts a valibot schema (any Standard Schema implementation works the same way) or a plain function that returns the parsed value or throws. On failure it throws ValidationError, whose issues array is the schema's issue list and whose message summarises them.

#Error shapes

Wrapper	On validation failure
`page.actions`	returns `fail(400, { errors: issues, values: rawForm })`
`route()`	throws `error(400, { message, issues })`

The action shape is what norns-ui's <Form> and <Field> consume; each field finds its message by matching errors[*].path[0].key against its name. The route shape reaches API clients as a 400 with a JSON body.

#Type inference

Use v.InferOutput<typeof schema> for the service's input type, as above, so the service signature and the schema cannot drift.

#The same schema on the wire

norns-tron derives a TRON wire schema from the same valibot object, which is how internal endpoints get the fastest serialization mode without a second shape definition.

#validate(schema, raw)

#Error shapes

#Type inference

#The same schema on the wire

#`validate(schema, raw)`