Answer & Solution
let and const are block scoped, but const cannot be re-assigned.
let and const is correct?
let and const are block scoped, but const cannot be re-assigned.
What will be the output of the following code?
let d; console.log(d); d = 15;
A). undefined
B). 15
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
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 e = 25; function test() { console.log(e); let e = 30; } test();
A). 25
B). 30
C). undefined
D). ReferenceError
What is the scope of a variable declared with let inside a loop?
A). Global scope
B). Function scope
C). Block scope
D). Module scope
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 h = 40; { console.log(h); h = 45; } console.log(h);
A). 40 45
B). 45 45
C). undefined undefined
D). ReferenceError 45
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
Which keyword should be used to declare variables that do not get re-assigned?
A). let
B). const
C). var
D). function
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