Answer & Solution
h logs 40 from the outer scope, and the second logs the updated value 45.
let h = 40; { console.log(h); h = 45; } console.log(h);
h logs 40 from the outer scope, and the second logs the updated value 45.
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 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 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 e = 25; function test() { console.log(e); let e = 30; } test();
A). 25
B). 30
C). undefined
D). ReferenceError
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?
let d; console.log(d); d = 15;
A). undefined
B). 15
C). null
D). ReferenceError
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
What will be the output of the following code?
let i = 50; { let i = 55; console.log(i); } console.log(i);
A). 50 50
B). 55 50
C). 50 55
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
Which keyword should be used to declare variables that do not get re-assigned?
A). let
B). const
C). var
D). function