React Hooks Introducing React Hooks 3

Question 1

According to the Rules of Hooks, where can you call Hooks?

Accepted Answer

Only at the top level of a function component or custom Hook

Answer

Hooks must be called at the top level, not inside loops, conditions, or nested functions.

Question 2

Why must Hooks not be called inside conditionals or loops?

Accepted Answer

React relies on call order to preserve state between renders

Answer

React identifies each Hook's state by the order in which Hooks are called.

Question 3

From where are you allowed to call Hooks?

Accepted Answer

React function components and custom Hooks

Answer

Call Hooks only from React function components or from other custom Hooks.

Question 4

What tool helps enforce the Rules of Hooks automatically?

Accepted Answer

eslint-plugin-react-hooks

Answer

The eslint-plugin-react-hooks plugin enforces these rules during development.

Question 5

What is a custom Hook?

Accepted Answer

A JavaScript function whose name starts with 'use' and that may call other Hooks

Answer

A custom Hook is a function starting with 'use' that can call other Hooks to reuse logic.

React Practice Test