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
What will typeof null return in JavaScript?
A). null
B). undefined
C). object
D). number
Given let a = '10'; let b = 20;, what is the result of a + b?
A). 30
B). 1020
C). 30
D). NaN
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 happens when you add a number and a string in JavaScript?
A). An error is thrown
B). The number is converted to a string
C). The string is converted to a number
D). Both are converted to boolean
What is the type of the value returned by JSON.parse('null')?
A). null
B). string
C). object
D). undefined
What is the initial type of a variable declared with let a;?
A). null
B). number
C). undefined
D). object
Given the code: let y = 10; y = true;, what is the type of y after execution?
A). number
B). boolean
C). string
D). object
What is the type of the value returned by parseFloat('3.14abc')?
A). number
B). string
C). NaN
D). undefined
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