Node

Question 1

What is Node.js?

Answer 1

a JavaScript runtime that is asynchronous and event driven.

Environment that lets us execute JavaScript code that doesn’t use a browser

Question 2

What can Node.js be used for?

Answer 2

It can be used to write command line tools and server-side scripting, making JavaScript to be the language for both server and client side

Question 3

What is a REPL?

Answer 3

Read-Eval-Print-Loop. Takes user-made input and returns it one line at a time

Question 4

When was Node.js created?

Answer 4

May 27, 2009

Question 5

What back end languages have heard of?`

Answer 5

Python, JavaScript, Java, Ruby, C#, C++, PHP

Question 6

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

Answer 6

Its a global that provides info about and control over the current Node.js process

Question 7

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

Answer 7

Use the process variable

Question 8

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

Answer 8

Returns an array

Question 9

What is a JavaScript module?

Answer 9

It is a single ‘.js’ file meant to separate out some functionality

Question 10

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

Answer 10

‘module,’ ‘require,’ ‘exports,’ ‘__dirname,’ ‘__filename’

Question 11

Give 2 examples of truly global variables in a Node.js program.

Answer 11

• global
• console
• setTimeout()
• clearInterval()

Question 12

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

Answer 12

Allows data types to be returned from a module called by using ‘require()’

Question 13

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

Answer 13

the require() function.

The source module contains the desired functionality within its code, followed by exports.name = name

The calling module contains the name, using a require()

Question 14

What is a directory?

Answer 14

A file that lists locations to other files

Question 15

What is a relative file path?

Answer 15

Set of directions from the current directory to its destination

Question 16

What is an absolute file path?

Answer 16

A path to a file that has the entire path shown, from its root element to its final destination

Question 17

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

Answer 17

‘fs.’ module

Question 18

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

Answer 18

fs.writeFile()

Question 19

Are file operations using the ‘‘fs’ module synchronous or asynchronous?

Answer 19

Asynchronous

Question 20

What is a client?

Answer 20

A requester of services from a server

Question 21

What is a server?

Answer 21

A provider of services to one or many clients (does the processing)

Question 22

Which HTTP method does a browser issue to a web server when you visit a URL?

Answer 22

‘GET’

Question 23

What is on the first line of an HTTP request message?

Answer 23

• The type of request (GET, POST, PUT), known as an HTTP method
• The URL
• The HTTP version

Question 24

What is on the first line of an HTTP response message?

Answer 24

• The protocol
• The status code (200, 404, etc)
• The human readable status (Success, file not found, etc.)

Question 25

What are HTTP headers?

Answer 25

A space for clients/servers to pass additional information about a request to each other, known as meta info

Question 26

Is a body required for a valid HTTP message?

Answer 26

No, it is not required

Question 27

What is NPM?

Answer 27

Nope Package Manager

Question 28

What is a package?

Answer 28

a file or directory

Question 29

How can you create a ‘package.json’ with ‘npm’?

Answer 29

Use the CLI command npm init --yes

Question 30

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

Answer 30

• A dependency is a package from an external source that is used in your program, making your program dependent on it
• The npm install (package name) command automatically adds the dependency to the package.json file. Otherwise, include it in the package.json file.

Question 31

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

Answer 31

It automatically adds the dependency into the package.json file

Question 32

How do you add ‘express’ to your package dependencies?

Answer 32

npm install express

Question 33

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

Answer 33

listen() method

Question 34

How do you mount a middleware with an Express application?

Answer 34

the Use method of the App object

Question 35

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

Answer 35

• req - the request object
• res - the response object
• next() - the next middleware function in the application’s request-response cycle

Question 36

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

Answer 36

application/json

Question 37

What is the significance of an HTTP request’s method?

Answer 37

It signifies the intent of the request, and can help a server developer design how a request should be handled

Question 38

What does the ‘express.json()’ middleware do and when would you need it?

Answer 38

Allows for parsing of JSON requests on requests made to an endpoint (route)
You need it when you are expecting to receive JSON requests and want to work with the JSON data as a JavaScript object

Question 39

What is Webpack?

Answer 39

A module bundler, compiling many files into one file

Question 40

How do you add a ‘devDependency’ to a package?

Answer 40

npm install –save-dev

Question 41

What is an NPM script?

Answer 41

They are scripts made available in the package.json file that allow you to run commands from NPM

Question 42

How do you execute Webpack with ‘npm run’?

Answer 42

Add a build to the NPM package.json’s scripts section, with the command being just webpack

Question 43

What does ‘express.static()’ return?

Answer 43

A function serveStatic

Question 44

What is the local ‘_dirname’ variable in a Node.js module?

Answer 44

The absolute path directory name of the module

Question 45

What does the ‘join()’ method of Node’s ‘path’ module do?

Answer 45

Joins strings together into a coherent path