Limitations

Inference is only as precise as the schema literal TypeScript can see. A shape built dynamically infers as an index signature, with no named fields:

import * as s
 from '@sanity-labs/typed-schema'

const shape
: Record
<string, ReturnType
<typeof s
.string
>> = {}
for (const key
 of ['firstName', 'lastName']) {
  shape
[key
] = s
.string
()
}

const Person
 = s
.object
(shape
)

type Person
 = s
.Infer
<typeof Person
>

const result
 = s
.parse
(Person
, {firstName
: 'Grace', lastName
: 'Hopper'})

if (result
.ok
) {
  // typed as {[x: string]: string}, so a typo like person.fristName compiles
  const person = result
.value
      
const person: {
    [x: string]: string;
}
}

Write shapes as literals (object({firstName: string(), lastName: string()})) to get narrow types.

The schema types reference lists what each creator accepts and what is a type error. Two of the rules for union() are easy to miss:

Union members must all be primitives, all documents, or all typed objects, references, images, files and blocks. See union().
Pass union() members that include a reference() inline, or declare the variable with as const, so that union() can count the references.

Limitations ​

Limitations