typescript - Yup InferType for array of strings not working as expected

Question

I'm trying to use Yup to define a schema and generate a Typescript Type that I can use for my objects.

Using InferType seems to work fine for strings and objects, but there's unexpected behavior for arrays. When required() or defined() is used with of(), the types stop working as I would expect.

NOTE: the validation functionality is working fine; I'm only having trouble with InferType

Ideal: InferType combines all operations to the expected type string[]

const schema = yup.array().required().of(yup.string().required());
type SchemaType = yup.InferType<typeof schema>;

// Type should be `string[]`
const schemaInstance: SchemaType = ["string1"];

Actual Scenario 1: array is string[] | undefined

const schema = yup.array().required().of(yup.string().required());
type SchemaType = yup.InferType<typeof schema>;

// Type is `string[] | undefined` so the following line compiles
const schemaInstance: SchemaType = undefined;

Actual Scenario 2: array is any

const schema = yup.array().of(yup.string().required()).required();
type SchemaType = yup.InferType<typeof schema>;

// Type is `any` so the following line compiles
const schemaInstance: SchemaType = {};

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Is there a way to make these types work as expected for an array of strings?

question from:https://stackoverflow.com/questions/65853623/yup-infertype-for-array-of-strings-not-working-as-expected

Answer 1

Waitting for answers