React

Question 1

Why use functional components over class based components?

Answer 1

1. Less code
2. Easier to understand
3. Stateless
4. Simpler to test
5. No ‘this’ binding
6. Easier to extract smaller components

Question 2

Why should we keep our components small?

Answer 2

Small components are easier to:
Read
Test
Maintain
Reuse

Question 3

Why use arrow functions when declaring methods in class based components?

Answer 3

In order to bind the this keyword to the class.

Question 4

When should we use a function, rather than an object, in this.setState?

Answer 4

When the new state we want to set rely on the previous state.

Question 5

What can the function we can pass to this.setState() take as arguments?

this.setState((?,?) => {

});

Answer 5

prevState, props

Question 6

What is prop-types and what is its purpose?

Answer 6

It is an external library for typechecking props

Question 7

How to use prop-types?

Answer 7

import PropTypes from ‘prop-types’

ComponentName.propTypes = {
name: PropTypes.string.isRequired
}

https://reactjs.org/docs/typechecking-with-proptypes.html