ReactJS

ReactJS - Keys and Ref

⛪ Computer Science and Engineering > ReactJS

Test your knowledge of ReactJS Keys and Ref with our interactive and challenging MCQ (Multiple Choice Questions) quiz. Covering topics such as key prop, ref prop, callback refs, and forwarding refs, our quiz is designed to help you improve your understanding of ReactJS Keys and Ref and prepare for interviews or exams.

Q 1: Ref is used to refer an/a element/component returned by _______________.

  • A react()
  • B reduce()
  • C refer()
  • D render()

Q 2: If our elements are dynamic, React can keep track of the changes using keys.

  • A True
  • B False

Q 3: We can go for ________ when there is a possibility that our user could change the data.

  • A Ref
  • B Both the options
  • C Keys
  • D None of the options

Q 4: An altered component may be uniquely identified with the help of ref.

  • A False
  • B True

Q 5: Keys used within arrays should be globally unique.

  • A True
  • B False

Q 6: To Prevent firing of the component's lifecycle methods you can use null from render method.

  • A True
  • B False

Q 7: Which lifecycle event is invoked before rendering and when new props or state is being received?

  • A render()
  • B componentWillUpdate()
  • C componentDidUpdate()
  • D shouldComponentUpdate()

Q 8: Batching of multiple setState() calls in a single update is possible.

  • A False
  • B True

Q 9: If you create an element, you cannot change its ________.

  • A Events
  • B Children and State
  • C State
  • D Children