Variables - var, let & const

This video tutorial covers the basics of variable declaration in JavaScript, focusing on the use of VAR, let, and const. It explains how to create, reassign, and initialize variables, and discusses naming conventions. The tutorial also highlights the differences between let and const, particularly in terms of block scope, and clarifies common misconceptions about using const with arrays and objects.

Which keyword was introduced in ES6 for variable declaration?

• float

• int

• let

• var

What is the initial value of a variable declared with var but not assigned?

• empty string

• null

• 0

• undefined

What is a common use case for initializing a variable without a value?

• To use in a conditional statement

• To declare a function

• To create a constant

• To start a loop

Which character is not allowed at the start of a JavaScript variable name?

• Number

• Underscore

• Dollar sign

• Letter

What is the recommended naming convention for multi-word variables in JavaScript?

• lowercase

• snake_case

• PascalCase

• camelCase

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

• name!

• $name

• _name

• 1name

How does let differ from var in terms of scope?

• let is function-scoped

• let is block-scoped

• let is globally-scoped

• let has no scope

What happens if you try to reassign a const variable?

• It changes the value

• It does nothing

• It creates a new variable

• It throws an error

Can you change the properties of an object declared with const?

• No, unless it's a number

• Yes, but only if it's a string

• No, properties are immutable

• Yes, you can change properties

Which keyword should you use if you want to ensure a variable's value doesn't change?

• int

• var

• const

• let