What is the result of the following code: let x = 5; x = 'hello'; console.log(typeof x);?
A). number
B). string
C). undefined
D). object
How can you check if a variable is an array in JavaScript?
A). typeof variable === 'array'
B). Array.isArray(variable)
C). variable instanceof array
D). variable.constructor === array
What will typeof NaN return in JavaScript?
A). number
B). NaN
C). undefined
D). object
Given let a = '10'; let b = 20;, what is the result of a + b?
A). 30
B). 1020
C). 30
D). NaN
What is the type of the value returned by JSON.parse('null')?
A). null
B). string
C). object
D). undefined
What is the result of typeof [] in JavaScript?
A). array
B). object
C). list
D). undefined
What is the type of the value returned by parseFloat('3.14abc')?
A). number
B). string
C). NaN
D). undefined
Which type conversion happens automatically in the expression 3 + '5'?
A). Number to String
B). String to Number
C). Boolean to String
D). Number to Boolean
What is the initial type of a variable declared with let a;?
A). null
B). number
C). undefined
D). object
What does it mean that JavaScript is dynamically typed?
A). Variables do not have types
B). Variables can change type
C). Variables must be declared with a type
D). Variables cannot change type