Node.js

Question 1

What is Node.js?

Answer 1

allows you to do js outside of the browser

Question 2

What can Node.js be used for?

Answer 2

build and launch apps from your computer

Question 3

What is a REPL?

Answer 3

read eval print loop that allows you to input commands, execute them, and return results

Question 4

When was Node.js created?

Answer 4

2009?

Question 5

What back end languages have you heard of?

Answer 5

C++ python C ruby go javascript java

Question 6

What is a computer process?

Answer 6

it is an instance of a computer program that is being executed by one or many threads

Question 7

Roughly how many computer processes are running on your host operating system?

Answer 7

6 apps running, 132 background processes

Question 8

Why should a full stack web developer know that computer processes exist?

Answer 8

know what sort of burden you are putting on a computer with your app

Question 9

What is the process object in a Node.js program?

Answer 9

The projcess object is a global that provides information about, and control over, the current Node.js process. As a global, it is always available to Node.js applications without using require(). It can also be explicitly accessed using require()

Question 10

How do you access the process object in a Node.js program?

Answer 10

You can access it by using console logging it or you can access it’s children by index
it is global so you can access it whenever

Question 11

What is the data type of process.argv in Node.js?

Answer 11

array of strings

Question 12

What is a JS module?

Answer 12

a simple part of a more complex, larger system

a file within many files for js

Question 13

What values are passed into a Node.js module’s local scope?

Answer 13

exports, require, module, __filename, __dirname

Question 14

Give two examples of truly global variables in a Node.js program

Answer 14

process console

Question 15

What is the purpose of module.exports in a Node.js module?

Answer 15

move code between files

Question 16

How do you import functionality into a Node.js module from another Node.js module?

Answer 16

use require

Question 17

What is the JavaScript Event Loop?

Answer 17

it is essentially a a queue of commands that are waiting to be run after the call stack has been filled and emptied

Question 18

What is different between “blocking” and “non-blocking” with respect to how code is executed?

Answer 18

blocking is essentially code that is synchronous while nonblocking is code that is asynchronous

Question 19

What is a directory?

Answer 19

a folder

Question 20

What is a relative file path?

Answer 20

the url of a file that is relative to the url of the file that you are using

Question 21

What is an absolute file path?

Answer 21

the absolute file path is the exact route of the file in question

Question 22

What module does Node.js include for manipulating the file system?

Answer 22

fs

Question 23

What method is available in the Node.js fs module for writing data to a file?

Answer 23

fs.writeFile

Question 24

Are file operations using the fs module synchronous or asynchronous?

Answer 24

both

Question 25

What is NPM?

Answer 25

it stands for node package manager and it is a software registry where you can share packages

Question 26

What is a package?

Answer 26

packages are reusable code, and are sometimes called modules
a package.json file:
- lists the packages your project depends on
- specifies versions of a package that your project can use using semantic versioning rules
- makes your build reproducible, and therefore easier to share with other developers

Question 27

How can you create a package.json with npm?

Answer 27

make sure that you are in your root directory and you need to run npm init
to make a default package.json using information extracted from the current directory, use the npm init command with the –yes or -y flag

Question 28

What is a dependency and how do you add one to a package?

Answer 28

this is a package that your code depends on; when you run npm install, npm will download dependencies and devDependencies that are listed in package.json that meet the semantic version requirements listed for each

Question 29

What happens when you add a dependency to a package with npm?

Answer 29

it gets added to the node-modules directory that is either in your directory or newly created, and it is listed as a dependency in the package.json file

Question 30

How do you add express to your package dependencies?

Answer 30

npm install express

Question 31

What Express application method starts the server and binds it to a network PORT?

Answer 31

listen

Question 32

How do you mount a middleware with an Express application?

Answer 32

use method

Question 33

Which objects does an Express application pass to your middleware to manage the request/response lifecycle of the server?

Answer 33

request and response

Question 34

What is the appropriate Content-Type header for HTTP messages that contain JSON in their bodies?

Answer 34

application/json