Using the Effect Hook. What is the Effect Hook?

Ref: https://reactjs.org/docs/hooks-effect.html

1. Hooks are a new addition to React 16.8.
   
   
2. They let you use state and other React features without writing a class.
   
   
3. What does useEffect do? By using this Hook, you tell React that your component needs to do something after render.
   
   
4. React will remember the function you passed (we’ll refer to it as our “effect”), and call it later after performing the DOM updates.
   
   
5. Hooks only works in the functional components. so if you want to use useEffect or any other hook you have to use functional components.
   
   
6. use effect keeps calling itself if you specifically do not specify an empty array at the end of the useEffect.

Eg:

useEffect( () => {

    

}, []); // empty array specified