Many people choose to think of React as the V in MVC.
React is all about building reusable components. In fact, with React the only thing you do is build components.
Render React Component on the page
Hook up the data model
props are immutable: they are passed from the parent and are "owned" by the parent.
To implement interactions, we introduce mutable state to the component. this.state is private to the component and can be changed by calling this.setState(). When the state updates, the component re-renders itself.
componentDidMount is a method called automatically by React after a component is rendered for the first time. The key to dynamic updates is the call to this.setState()