Answer & Solution
let
declarations are hoisted to the top of their block scope, not function or global scope.
let
variables hoisted?
let
declarations are hoisted to the top of their block scope, not function or global scope.
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
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
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 advantage of using let
over var
?
A). let
allows for function scoping
B). let
does not get hoisted
C). let
avoids issues related to the temporal dead zone
D). let
is globally 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
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 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
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