Modern JavaScript from the Beginning - Second Edition - Block Scope

The video tutorial explains the concept of block level scope and the differences between using var, let, and const to declare variables. It demonstrates how var is not block scoped, unlike let and const, which are. The tutorial includes examples of using let in loops and highlights the function scope of var. It also discusses how global variables declared with var are added to the window object, unlike those declared with let or const.

What is the main difference between 'var' and 'let' in terms of scope?

• Neither 'var' nor 'let' is block-scoped

• Both 'var' and 'let' are block-scoped

• 'let' is block-scoped, 'var' is not

• 'var' is block-scoped, 'let' is not

What happens when you try to access a 'let' variable outside its block?

• It logs the last value

• It returns undefined

• It throws a reference error

• It returns null

Which of the following is true about 'var' when used inside a block?

• 'var' is global-scoped

• 'var' is function-scoped

• 'var' is block-scoped

• 'var' is not scoped at all

What is the scope of a variable declared with 'const' inside a block?

• Global scope

• Block scope

• No scope

• Function scope

Why is it recommended to use 'let' and 'const' over 'var'?

• They are more modern

• They are faster

• They provide block scoping

• They are easier to type

What is the result of accessing a 'var' variable declared inside a function from outside the function?

• It returns undefined

• It logs the value

• It returns the value

• It throws a reference error

How does a global variable declared with 'var' differ from one declared with 'let'?

• Only 'let' is added to the window object

• Only 'var' is added to the window object

• Both are added to the window object

• Neither is added to the window object