React State Management 2

Question 1

When you call the state setter from useState, what does React do to the component?

Accepted Answer

Schedules a re-render of the component

Answer

Calling a setter schedules a re-render with the new state value.

Question 2

Which is the correct way to update state that depends on the previous state?

Accepted Answer

setCount(prev => prev + 1)

Answer

Passing an updater function guarantees you act on the latest state.

Question 3

Why should you never mutate state arrays directly with push() in React?

Accepted Answer

React won't detect the change and may not re-render

Answer

React relies on a new reference to detect changes, so you must create a new array.

Question 4

What is the initial value of state declared as useState()?

Accepted Answer

undefined

Answer

With no argument, the initial state is undefined.

Question 5

Which hook is best suited for managing complex state logic with multiple sub-values?

Accepted Answer

useReducer

Answer

useReducer centralizes complex state transitions in a reducer function.

React Practice Test