I created a [codesandbox](https://codesandbox.io/s/nifty-jackson-rq6il) that shows 3 formik fields: first name, last name, and name.

I'm trying to make the field `name` display `${firstName} ${lastName}` only until the user modifies the `name` field themselves, and so the condition `name === firstName + ' ' + lastName` fails, after which the `name` field should not be automatically updated anymore.

The challenge is that I'm trying to make this code live in the `MyContactForm.tsx` file since I need to be reusing that logic of inter-field dependency in other similar `My*Form.tsx` components thereafter, and therefore reuse the "generic" `MyForm.tsx` component without change.