Introduction to Formik

Formik is one of those libraries that came at just the right time to resolve a long-standing issue: how we handle really complex forms in React. Complex forms can include multiple embedded forms, dynamic fields and validation, or handling asynchronous checks with the backend. Prior to Formik, there were numerous options available, for example, using Redux-Form or React-Redux-Form, which basically stored the form state in a Redux store. That worked for a while, but complexity and peculiar bugs started to come in. Having to fix a gigantic form that was working once upon a time but now is not is something that we should all be wary of as it can happen all the time. For example, when we have a form where the validation happens in different stages and the outcome of each step depends on how the previous steps validate, it becomes difficult to find even the smallest bugs. And testing this logic can become even trickier because you would need to cover all the scenarios...