Answer & Solution
b before its declaration in the same block results in a ReferenceError.
{ console.log(b); let b = 20; }
b before its declaration in the same block results in a 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
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
In which scope are let variables hoisted?
A). Function scope
B). Block scope
C). Global scope
D). Module scope
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
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
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 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?
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?
console.log(a); let a = 10;
A). undefined
B). 10
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