React props

const element = <Welcome name="Sara" />;

When React sees an element representing a *user-defined component*, 
it passes *JSX attributes* to this component as a single object. We call this object *“props”*.


When an element type starts with a lowercase letter, it refers to a built-in component like <div> or <span> 
and results in a string 'div' or 'span' passed to React.createElement. 
**Types that start with a capital letter like <Foo /> compile to React.createElement(Foo)** 
and correspond to a component defined or imported in your JavaScript file.

All React components must act like pure functions with respect to their props. - React Docs