ES6

Question 1

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

Answer 1

Code surrounded by curly braces. Ex: if statement, function, for loop

Question 2

What does block scope mean?

Answer 2

the block scope restricts the variable that is declared inside a specific block

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 a var that cannot be reassigned while let is able to be reassigned

Question 5

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

Answer 5

you aren’t reassigning a new array, you are just pushing a new value inside

Question 6

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

Answer 6

If you want to change the var use let, if you don’t want to change use const

Question 7

What is the syntax for writing a template literal?

Answer 7

back ticks instead of quotes

Question 8

What is “string interpolation”?

Answer 8

process in which an expression is inserted or placed in the string.

Question 9

What is destructuring, conceptually?

Answer 9

how you get property values or array elements all on one line

Question 10

What is the syntax for Object destructuring?

Answer 10

keyword const or let, curly braces and property and variable names inside curly braces and object it came from

Question 11

What is the syntax for Array destructuring?

Answer 11

keyword const or let, square brackets and property and variable names inside square brackets and object it came from

Question 12

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

Answer 12

if curly braces or square brackets are on left side of assignment operator then you are destructuring

Question 13

What is the syntax for defining an arrow function?

Answer 13

const or let then varName = (parameter) => {code block}

Question 14

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

Answer 14

it does not require a return statement

Question 15

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

Answer 15

It is the parents code block

Question 16

What are the three states a Promise can be in?

Answer 16

pending, fulfilled, rejected

Question 17

How do you handle the fulfillment of a Promise?

Answer 17

you use the then method

Question 17

How do you handle the fulfillment of a Promise?

Answer 17

you use the then method

Question 18

How do you handle the rejection of a Promise?

Answer 18

you use the catch method

Question 19

What is Webpack?

Answer 19

It allows us to take all of script files and combine them into one file

Question 20

How do you add a devDependency to a package?

Answer 20

npm install –save-dev “package name”

Question 21

What is an NPM script?

Answer 21

a way to automate things using shell command

Question 22

How do you execute Webpack with npm run?

Answer 22

npm run build

Question 23

How are ES Modules different from CommonJS modules?

Answer 23

it uses import and export not the require method

Question 24

What kind of modules can Webpack support?

Answer 24

ecmascript, commonjs, web assembly