ES6

Question 1

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

Answer 1

Code blocks are usually found in loops or functions

Curly braces

Question 2

What does block scope mean?

Answer 2

Block scope means it is only available in the local code block

Question 3

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

Answer 3

Block scoped ALWAYS

Question 4

What is the difference between let and const?

Answer 4

let can be reassigned a value but const is immutable (except array and objects) since they are pointing to a memory address

Question 5

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

Answer 5

because they are pointing to a memory address

Question 6

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

Answer 6

const for most part but if the variable changes throughout the block then use let

Question 7

What is destructuring, conceptually?

Answer 7

destructuring is assigning variables the value of the object properties

Question 8

What is the syntax for Object destructuring?

Answer 8

const {var1, var2, var3, …} = objectName

Question 9

What is the syntax for Array destructuring?

Answer 9

const [var1, var2, var3, …] = arrayName

Question 10

How can you tell the difference between destructuring and creating Object/Array literals?

Answer 10

destructuring has brackets on the left-hand side whereas creating Object/Array literals will have them on the right-hand side

Question 11

What is the syntax for writing a template literal?

Answer 11

use back ticks and ${} (dollar sign and curly braces)

Question 12

What is “string interpolation”?

Answer 12

it is brining the value of variables into a string

Question 13

What is the syntax for defining an arrow function?

Answer 13

() => {}

Question 14

When an arrow function’s body is left without curly braces, what changes in its functionality?

Answer 14

implicit return fires

Question 15

How is the value of this determined within an arrow function?

Answer 15

it encloses the actual ‘this’ and does not create it’s own ‘this’