What is state in React?
State of a component is an object that holds some information that may change over the lifetime of the component. We should always try to make our state as simple as possible and minimize the number of spiteful components. Let's create a user component with message state.
What are Pure Components?
React.PureComponent is exactly the same as React.Component except that it handles the shouldComponentUpdate() method for you. When props or state changes, PureComponent will do a shallow comparison on both props and state. Component on the other hand won't compare current props and state to next out of the box. Thus, the component will re-render by default whenever shouldComponentUpdate is called.
When to use a Class Component over a Function Component?
If the component needs state or lifecycle methods then use class component otherwise use function component. However, from React 16.8 with the addition of Hooks, you could use state, lifecycle methods and other features that were only available in class component right in your function component.
