What is the advantage of using let over var?

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

A). let

B). const

C). var

D). function

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?

let d; console.log(d); d = 15;

A). undefined

B). 15

C). null

D). ReferenceError

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

What will be the output of the following code?

let h = 40; { console.log(h); h = 45; } console.log(h);

A). 40 45

B). 45 45

C). undefined undefined

D). ReferenceError 45

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

A). let is function scoped, var is block scoped

B). let is block scoped, var is function scoped

C). Both are function scoped

D). Both are block scoped

Where should let variables be declared to avoid TDZ issues?

A). At the top of the global scope

B). At the bottom of their block scope

C). At the top of their block scope

D). Anywhere in the code

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

How can you avoid variable hoisting issues with let?

A). Declare variables at the bottom of the code

B). Use var instead

C). Declare variables at the top of their scope

D). Do not declare variables

What will be the output of the following code?

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

A). undefined

B). 10

C). null

D). ReferenceError