Ojective Question

react-mcqs - Set (3)

Correct Answer: Orange && Worng Answer: Red

1. Which of the following is used to access a function fetch() from h1 element in JSX?

(A). <h1>${fetch()}</h1>

(B). <h1>{fetch}</h1>

(C). <h1>${fetch}</h1>

(D). <h1>{fetch()}</h1>

View Answer

Explanation: The correct command is <h1>{fetch()}</h1>.

2. When setState() is called inside render() method, which of the following events takes place?

(A). duplicate key error

(B). repetitive output happiness on the screen

(C). nothing happens

(D). stackoverflow error

View Answer

Explanation: Stackoverflow error occurs when setState() is called inside render() method.

3. What happens if you render an input element with disabled = {false}?

(A). it will be rendered as enabled

(B). it will be rendered as disabled

(C). it will not be rendered at all

(D). None of the above

View Answer

Explanation: It will be rendered as enabled if you render an input element with disabled = {false}.

4. When is useReducer used over useState in React component?

(A). When we want to replace redux

(B). when we want to break our production app

(C). when we want to improve performance

(D). none of the above

View Answer

Explanation: When we want to replace redux, useReducer is used over useState.

5. React is a ___________

(A). JavaScript framework

(B). JavaScript library

(C). both a and b

(D). none of the above

View Answer

Explanation: React is a JavaScript library.

6. Choose the library which is most often associated with react?

(A). Sinon

(B). Chai

(C). Jest

(D). Mocha

View Answer

Explanation: Jest is most often associated with react.

7. What is used to handle code-splitting?

(A). React.lazy

(B). React.memo

(C). React.fallback

(D). React.split

View Answer

Explanation: React.lazy is used to handle code splitting.

8. Why is useLayoutEffect used?

(A). To complete the update

(B). to optimize for all devices

(C). To change the layout of the screen

(D). when you need the browser to paint before the effectors

View Answer

Explanation: When you need the browser to paint before the effect runs, useLayoutEffect used.

9. Which of the following terms commonly described react applications?

(A). Imperative

(B). Integrated

(C). Declarative

(D). closed

View Answer

Explanation: Declarative is commonly used to describe react applications.

10. Why is ref used?

(A). to bind the function

(B). to call a function

(C). to directly access the DOM node

(D). to refer to another JS file

View Answer

Explanation: Ref is used to directly access the DOM node.

1. Which of the following is used to access a function fetch() from h1 element in JSX?

2. When setState() is called inside render() method, which of the following events takes place?

3. What happens if you render an input element with disabled = {false}?

4. When is useReducer used over useState in React component?

5. React is a ___________

6. Choose the library which is most often associated with react?

7. What is used to handle code-splitting?

8. Why is useLayoutEffect used?

9. Which of the following terms commonly described react applications?

10. Why is ref used?

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