Given let a = '10'; let b = 20;, what is the result of a + b?
A). 30
B). 1020
C). 30
D). NaN
What will be the result of the following code: let z = '123'; z = Number(z); console.log(typeof z);?
A). string
B). number
C). undefined
D). boolean
What is the initial type of a variable declared with let a;?
A). null
B). number
C). undefined
D). object
What does the parseInt function do in JavaScript?
A). Converts a number to a string
B). Converts a string to an integer
C). Converts a boolean to a number
D). Converts an array to a number
In JavaScript, what will be the type of a variable x after x = 5 + true;?
A). number
B). string
C). boolean
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
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
What is the result of typeof [] in JavaScript?
A). array
B). object
C). list
D). undefined
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 will be the result of typeof function() {} in JavaScript?
A). function
B). object
C). undefined
D). method