Components and Props Quiz

Question 1

What happens if you declare a component inside another component's body?

Accepted Answer

React sees a new component type each render and remounts the subtree, losing its state

Answer

Nothing, it is a normal pattern

Answer

React throws a compile error

Answer

The inner component becomes a singleton

Question 2

Can a component change the props it receives?

Accepted Answer

No, props are read only and must not be modified by the receiving component

Answer

Yes, props are mutable objects

Answer

Only if the prop is an object

Answer

Only inside an event handler

Question 3

How should a child component change a value that lives in its parent?

Accepted Answer

Call a function the parent passed down as a prop

Answer

Assign to the prop directly

Answer

Import the parent and call setState on it

Answer

Use a global variable

Question 4

What is the children prop?

Accepted Answer

Whatever was placed between the component's opening and closing tags

Answer

A list of every nested component in the tree

Answer

An array of the component's state values

Answer

The component's own return value

Question 5

What does the rest pattern do here?

Accepted Answer

It collects all remaining props so they can be forwarded to the button element

Answer

It ignores every prop except variant

Answer

It creates a copy of the children

Answer

It resets the props to their defaults

Question 6

When does a default value in the destructuring pattern apply?

Accepted Answer

When the prop is missing or explicitly undefined

Answer

Only when the prop is null

Answer

On every render regardless of the value

Answer

Only for string props