Modern JavaScript from the Beginning - Second Edition - Variables and Constants

This video tutorial covers the basics of variables in JavaScript, including how to declare them using var, let, and const. It explains the importance of understanding data types and introduces the concept of scope. The tutorial also discusses naming conventions for variables, such as camelCase and PascalCase, and demonstrates how to reassign variables. Additionally, it covers the use of arrays and objects with const, and how to declare multiple variables at once. The video emphasizes the preference for using const unless reassignment is necessary.

Which keyword is not commonly used for declaring variables in modern JavaScript?

• function

• const

• let

• var

What is the main reason for introducing 'let' and 'const' in ES6?

• To simplify syntax

• To manage scope better

• To enhance security

• To improve performance

What error occurs if you try to use a 'let' variable before it is initialized?

• SyntaxError

• ReferenceError

• TypeError

• InitializationError

Which of the following is a valid variable name in JavaScript?

• 1name

• name1

• name-1

• name*1

What is the naming convention called where the first letter of each word is capitalized except the first word?

• kebab-case

• snake_case

• camelCase

• PascalCase

What happens if you try to reassign a 'const' variable?

• It reassigns the value

• It creates a new variable

• It silently fails

• It throws an error

How can you add a new element to a 'const' array?

• Reassign the array

• Directly assign a new value

• Use the push method

• Use the pop method

Which method is used to add a property to an object declared with 'const'?

• Use the push method

• Directly assign a new property

• Use the delete method

• Reassign the object

What is the result of logging an uninitialized 'let' variable?

• NaN

• null

• undefined

• 0

What is the preferred keyword for declaring variables that will not be reassigned?

• var

• let

• const

• function