What will be the output of the following code?

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

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

A). let

B). const

C). var

D). function

What is the 'temporal dead zone'?

A). The period during which a variable is declared but not yet initialized

B). The time when the variable is accessible throughout the program

C). The period after variable initialization

D). None of the above

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

What will be the output of the following code?

let f = 10; if (true) { console.log(f); let f = 20; }

A). 10

B). 20

C). undefined

D). ReferenceError

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

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

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

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(b); let b = 20; }

A). 20

B). undefined

C). null

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