Q
Which statement is true regarding the use of 'Undefined'?

Answer & Solution

Answer: Option B
Solution:
Using 'Undefined' to represent missing or uninitialized values is discouraged as it can lead to unexpected behavior and is often considered a mistake in programming.
Related Questions on Average

How do you assign a variable to have a value of 'Null'?

A). Using the assignment operator =.

B). Using the null keyword.

C). Using the undefined keyword.

D). Using the void operator.

How is 'Null' different from 'Undefined'?

A). Null represents variables that have been initialized but not declared.

B). Null represents an intentional absence of value or object reference.

C). Null is never used in programming.

D). Null is a substitute for 'Undefined'.

Which statement best describes the relationship between 'Undefined' and 'Null' in JavaScript?

A). Undefined and Null are interchangeable and can be used interchangeably in code.

B). Undefined and Null are distinct values representing different states in JavaScript.

C). Undefined is a subset of Null, encompassing all possible values of Null.

D). Null is a subset of Undefined, encompassing all possible values of Undefined.

What does the expression typeof null return in JavaScript?

A). null

B). object

C). undefined

D). function

How does the typeof operator behave when applied to an 'Undefined' value?

A). It returns 'undefined'.

B). It returns 'null'.

C). It throws an error.

D). It returns 'object'.

What does the expression null == undefined return in JavaScript?

A). 1

B). 0

C). undefined

D). null

How do you check if a variable has an 'Undefined' value in JavaScript?

A). Using the undefined keyword.

B). Using the null keyword.

C). Using the typeof operator.

D). Using the empty keyword.

Which of the following is an example of using 'Null' in JavaScript?

A). let user = null;

B). let user = undefined;

C). let user;

D). let user = '';

What is the result of the expression typeof undefinedVariable if undefinedVariable is not declared?

A). object

B). function

C). undefined

D). null

Which of the following is a valid use case for 'Null' in JavaScript?

A). Storing default values in variables.

B). Clearing or resetting object references.

C). Assigning placeholders in arrays.

D). Checking if a variable exists.