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

What will be the output of the following code?

console.log(a); let a = 10;

A). undefined

B). 10

C). null

D). ReferenceError

What will be the output of the following code?

for (let i = 0; i < 3; i++) { setTimeout(() => console.log(i), 0); }

A). 0 0 0

B). 3 3 3

C). 0 1 2

D). ReferenceError

What will be the output of the following code?

{ console.log(b); let b = 20; }

A). 20

B). undefined

C). null

D). ReferenceError

Which of the following is true about let declarations?

A). They are hoisted and initialized at the top of their scope

B). They are hoisted but not initialized

C). They are not hoisted at all

D). They are function scoped

Which keyword should be used to declare variables that do not get re-assigned?

A). let

B). const

C). var

D). function

What happens when you try to re-declare a let variable in the same scope?

A). It reassigns the value

B). It throws a SyntaxError

C). It re-declares the variable

D). It throws a TypeError

In which scope are let variables hoisted?

A). Function scope

B). Block scope

C). Global scope

D). Module scope

What will be the output of the following code?

let c = 5; { let c = 10; console.log(c); }

A). 5

B). 10

C). ReferenceError

D). undefined

Which statement about let and const is correct?

A). Both are block scoped, but only let can be re-assigned

B). Both are block scoped, but only const can be re-assigned

C). Only const is block scoped

D). Both are not block scoped

What will be the output of the following code?

let e = 25; function test() { console.log(e); let e = 30; } test();

A). 25

B). 30

C). undefined

D). ReferenceError