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
What is the primary difference between var and let?
A). Scope
B). Initialization
C). Data type
D). Assignment
What is the scope of a variable declared with let?
A). Global
B). Function
C). Block
D). Object
Which keyword should be used for a variable that might be reassigned?
A). const
B). let
C). var
D). function
Can const variables be reassigned in nested scopes?
A). Yes
B). No
C). Only if they are strings
D). Only in strict mode
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
Can const be used for objects and arrays?
A). No
B). Yes
C). Only for arrays
D). Only for objects
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 value of a const variable once it is assigned?
A). Can be changed later
B). Cannot be changed later
C). Depends on the data type
D). Undefined initially
What is the temporal dead zone in ES6?
A). Time between function calls
B). Period between variable declaration and initialization
C). Time between two loops
D). Interval between event listeners