Creating the new component

In this section, we’ll create the basic form of AppointmentsDayView: a list of appointment times for the day. We won’t build any interactive behavior for it just yet.

We’ll add our new component into the same file we’ve been using already because so far there’s not much code in there. Perform the following steps:

Placing components

We don’t always need a new file for each component, particularly when the components are short functional components, such as our Appointment component (a one-line function). It can help to group related components or small sub-trees of components in one place.

1. In test/Appointment.test.js, create a new describe block under the first one, with a single test. This test checks that we render a div with a particular ID. That’s important in this case because we load a CSS file that looks for this element. The expectations in this test use the DOM method, querySelector...