Generate initialValues, types from Yup Schema

[webarnes]

This is an idea I had and thought someone might find it interesting and put the time in to explore it further.

I've got a lot of duplication going on with my form: a Yup schema, a Typescript type, initial values, and the form itself. It seems like there should be a way to combine all or some of those and reduce the boilerplate.

This works in regular Javascript:

const PersonSchema = Yup.object().shape({
    name: Yup.string().default('John')
});

const initialValues = YupSchema.cast({});
// {
//    name: 'John'
// }

In Typescript, the following seems to work:

const PersonSchema = Yup.object().shape({
    name: Yup.string().default('John')
});

type Person = Yup.InferType<typeof PersonSchema>

const initialValues = YupSchema.cast({});

I ran into some roadblocks with my more complicated schema (enums and nested properties don't work right) but I'm optimistic that there is a solution out there to describe your schema once and generate the type and initial values. The first method will work with more complicated schemas but you need to cast them as the proper type.