Week 11: State, events and forms

Score 4 out of 5 to complete this week.

1. 1. What happens when you call a state setter from useState?

   Nothing until reloadReact re-renders the component with the new valueThe page reloadsThe DOM is replaced
2. 2. Which update is safest when the new value depends on the old one?

   setCount(count + 1)setCount(c => c + 1)count++setCount(++count)
3. 3. How should you update an object in state?

   Mutate it then call setState(sameObject)Create a new object: setUser({ ...user, name })Use deleteAssign to state directly
4. 4. What is a controlled input?

   An input with a refAn input whose value comes from state and updates through onChangeA disabled inputAn input inside a form
5. 5. Two sibling components need the same state. Where should it live?

   In bothIn their closest common parentIn localStorageIn a CSS variable