Are variables declared with let and const accessible before they are declared?
A). Yes
B). No
C). Only in strict mode
D). Only if they are numbers
Which keyword allows block-level scope in ES6?
A). var
B). let
C). function
D). var and function
What happens if you try to access a let variable before its declaration?
A). Returns undefined
B). Throws a ReferenceError
C). Returns null
D). Returns an empty string
Which of the following statements about const and objects is true?
A). Objects declared with const are immutable
B). Properties of objects declared with const can be changed
C). The reference of objects declared with const can be changed
D). const cannot be used with objects
Which keyword should be used for a variable that might be reassigned?
A). const
B). let
C). var
D). function
What will the following code output: { let y = 5; { let y = 10; console.log(y); } }?
A). 5
B). 10
C). undefined
D). ReferenceError
What is the primary difference between var and let?
A). Scope
B). Initialization
C). Data type
D). Assignment
Can a let variable be redeclared in the same scope?
A). Yes
B). No
C). Only if it is a string
D). Only if it is a number
What is the output of the following code: let z = 3; z = 5; console.log(z);?
A). 3
B). 5
C). undefined
D). ReferenceError
What will be the output of the following code: let x = 10; { let x = 20; } console.log(x);?
A). 10
B). 20
C). undefined
D). ReferenceError