A component is a JavaScript class/function that optionally accepts inputs e.g. properties(props and returns a React element that describes how it should look:
You can have functional components and class components
When should you use a functional component?
when what you are writing doesn't hold or manage states
pretty much all the do is presentational stuff ( take properties and output UI elements which are rendered to the page)
e.g. const Greeting = () => <h1>Hi, I’m a dumb component!</h1>;
When should you use a class component?
When dealing with state
Basic Components:
Text - displays text
View - layout/positioning
Image - displays images
TextInput - user input via keyboard
ScrollView - creates a container which can host multiple components and views