State a component memory

Question 1

What is a state variable used for in a component?

Answer 1

To remember some information between renders.

State variables store data that can change over time within a component.

Question 2

How are state variables declared in React?

Answer 2

By calling the useState Hook.

The useState Hook is a built-in function that allows you to add state to functional components.

Question 3

What are Hooks in React?

Answer 3

Special functions that start with use, allowing you to hook into React features like state.

Common hooks include useState, useEffect, and useContext.

Question 4

Where must Hooks be called in a React component?

Answer 4

At the top level of a component or another Hook.

Hooks should not be called conditionally or inside loops.

Question 5

What does the useState Hook return?

Answer 5

A pair of values: the current state and the function to update it.

This allows for both reading and updating the state in the component.

Question 6

Can you have more than one state variable in a React component?

Answer 6

Yes, you can have more than one state variable.

React matches them up by their order of declaration.

Question 7

Is state private to a component in React?

Answer 7

Yes, state is private to the component.

Each instance of a component maintains its own state.