Q
What will be the output of the code above?

Answer & Solution

Answer: Option B
Solution:
Although person is a constant, its properties can be modified. In this case, person.age is modified to 31 and the output will be 31.
Related Questions on Average

How can you declare a constant named PI with a value of 3.14 in JavaScript using const?

A). A. const PI = 3.14;

B). B. PI = 3.14;

C). C. let PI = 3.14;

D). D. var PI = 3.14;

What happens if you try to reassign a value to a constant declared using const?

A). A. SyntaxError

B). B. TypeError

C). C. ReferenceError

D). D. No error, value is reassigned

What does the const keyword signify in JavaScript?

A). A. Constant variable

B). B. Mutable variable

C). C. Global variable

D). D. Block-scoped variable

What will be logged to the console?

A). A. 'John'

B). B. 'Jane'

C). C. Error

D). D. Undefined

Which statement is true regarding the const keyword in JavaScript?

A). A. Constants declared with const are hoisted

B). B. Constants declared with const can be reassigned

C). C. Constants declared with const have global scope

D). D. Constants declared with const are immutable

What will be logged to the console after 1 second?

A). A. 0 1 2

B). B. 3 3 3

C). C. 0 0 0

D). D. Error

Which keyword is used to declare block-scoped variables in JavaScript?

A). A. var

B). B. let

C). C. const

D). D. block

Which of the following statements about const is true?

A). A. Variables declared with const can be reassigned

B). B. const variables have function scope

C). C. const variables cannot be used in loops

D). D. const variables are block-scoped

What is the primary advantage of using block scope in JavaScript?

A). A. Reducing code size

B). B. Preventing variable hoisting

C). C. Avoiding global variables

D). D. Improving performance

What is the purpose of using block scope in JavaScript?

A). A. To declare constants

B). B. To prevent variable hoisting

C). C. To improve code performance

D). D. To create global variables