Master JavaScript Arrays & Objects | MCQs – Module 4

1. Which data type is used to store multiple values in a single variable?

a) String
b) Number
c) Array
d) Object

2. Which method is used to add a new element to the end of an array?

a) pop()
b) push()
c) shift()
d) map()

3. What does the map() method do?

a) Removes elements from an array
b) Changes the original array
c) Creates a new array after applying a function
d) Sorts the array

4. What will be the output?

let nums = [1,2,3];
let result = nums.map(n => n * 2);
console.log(result);

a) [1, 2, 3]
b) [2, 4, 6]
c) [3, 6, 9]
d) Error

5. Which method filters elements based on a condition?

a) map()
b) reduce()
c) filter()
d) push()

6. What will this code return?

let number = [5, 10, 15];
let result = numbers.filter(n => n > 10);

a) [5, 10]
b) [15]
c) [10, 15]
d) []

7. Which method is used to reduce an array to a single value?

a) map()
b) filter()
c) reduce()
d) push()

8. What will be the output?

let nums = [1, 2, 3];
let sum = nums.reduce((a, b) => a + b, 0);
console.log(sum);

a) 3
b) 5
c) 6
d) 0

9. How do you access the value of name in this object?

let student = { name: "John", age: 20 };

a) student[name]
b) student->name
c) student.name
d) student::name

10. Which format is used to store and exchange data?

a) XML
b) HTML
c) JSON
d) CSS

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