Given let a = "10"; let b = 20;, what is the result of a + b?

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 null return in JavaScript?

A). null

B). undefined

C). object

D). number

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 will be the result of typeof function() {} in JavaScript?

A). function

B). object

C). undefined

D). method

What is the initial type of a variable declared with let a;?

A). null

B). number

C). undefined

D). object

What is the type of the value returned by JSON.parse('null')?

A). null

B). string

C). object

D). undefined

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

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

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 the following code: let z = '123'; z = Number(z); console.log(typeof z);?

A). string

B). number

C). undefined

D). boolean