Mastering React Test-Driven Development

Scaffolding the saga and reducer

There are two new types of function: sagas and reducers. They work in tandem with each other. The approach we'll use in this section is to build a single Redux action that works its way through both a saga and a reducer. We will "scaffold" barebones implementation for both, for that single action, before fleshing out the functions with more detail.

For reference, here's the existing code that we'll be extracting from CustomerForm. It's all helpfully in one function, doSave, even though it is quite long:

const doSave = async () => {  setSubmitting(true);  const result = await window.fetch('/customers', {    method: 'POST',    credentials: 'same-origin',    headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(customer) ...