Field have to be able to add defaultValue from props

[chilijung]

Current mechanism directly shows value from source and update value to the source. But sometimes it's not enough.

But in some cases, we might need to insert a defaultValue from Canner schema.

let's say, we need a form to create a product, and the productId should generate while I click the add button and also it should be disabled so users is not allow to change it. So in order to do that I'll add a schema as below.

<string
  keyName="productId"
  disabled
  defaultValue={() => shortId.generate()...}/> // I could use shortId or timestamp to generate a immutable defaultValue.