const let

Question 1

What is a code block? What are some examples of a code block?

Answer 1

code block is within the opening and closing curly brace of a function. function definition, if statements, loops

Question 2

What does block scope mean?

Answer 2

Variable only accessible within the block. not initialized to any value, not attached to global object.

Question 3

What is the scope of a variable declared with const or let?

Answer 3

Block scope

Question 4

What is the difference between let and const?

Answer 4

const is read-only, identifiers are uppercase, can’t be reassigned. Const can change value of property, but not reassign. Let are mutable, can change value.

Question 5

Why is it possible to .push() a new value into a const variable that points to an Array?

Answer 5

We are not reassigning or changing memory address, but adding to an object or property to the array

Question 6

How should you decide on which type of declaration to use?

Answer 6

Use const if you don’t intend to modify a variable. Let if value changes, if not sure default to const.