The key abstraction that React provides is that of a component. To reiterate, a component is some thing that is being rendered in the browser. It could be a button, a form with a bunch of fields in it, a navigation bar at the top of the page, a single input field, etc. Any of these could be its own component. React doesn't place any restrictions on how large or small a component can be. You could have an entire static site encapsulated in a single React component, but that at that point you may as well not be using React. So the first thing to remember about a component is that a component must render something. If nothing is being rendered from a component, then React will throw an error.
Let's write the most basic of components we can possibly write. Inside of BasicComponent.js, first import React at the top of the file. Our most basic of
components looks like this:
import React from 'react';
const BasicComponent = () => <div>Hello World!</div>;