What is the data type of the value undefined in JavaScript?

Which of the following is not a valid data type in JavaScript?

A). Array

B). Symbol

C). Map

D). Tuple

Which operator checks if an object is an instance of a specific object type in JavaScript?

A). instanceof

B). typeof

C). isInstanceof

D). isTypeOf

Which of the following is a primitive data type in JavaScript?

A). Object

B). Array

C). Function

D). Boolean

What is the data type of the value 'null' (with quotes) in JavaScript?

A). String

B). Number

C). Null

D). Undefined

Which data type represents unique and immutable values in JavaScript introduced in ES6?

A). Symbol

B). Object

C). Array

D). Function

What is the outcome of typeof undefined in JavaScript?

A). String

B). Undefined

C). Null

D). Number

What will let x = '10'; let y = x - 5; console.log(y); output in JavaScript?

A). '5'

B). 5

C). '10'

D). 10

What does NaN represent in JavaScript?

A). Not a Number

B). Infinity

C). Positive Infinity

D). Negative Infinity

What will the following code snippet output: let a = 10; a += '5'; console.log(a); in JavaScript?

A). '105'

B). 105

C). 15

D). '15'

What will let x = null; console.log(typeof x); output in JavaScript?

A). Object

B). Null

C). Undefined

D). Number