Node part 2

Question 1

What is a client?

Answer 1

the one that makes service requests

Question 2

What is a server?

Answer 2

the one that provides a resource or service

Question 3

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

Answer 3

Get request

Question 4

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

Answer 4

Their start-line contain three elements:
HTTP Method (get, post, put),
Request Target: (URL),
HTTP Version

Question 5

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

Answer 5

Status line:{
Protocol Version,
Status code,
Status Text
}

Question 6

What are HTTP headers?

Answer 6

List of key value pairs in the header of the response

Question 7

Is a body required for a valid HTTP message?

Answer 7

No

Question 8

What is NPM?

Answer 8

a package manager for JavaScript: website, command line interface, and registry:
to shared data and packages, etc.

Question 9

What is a package?

Answer 9

• a folder containing a package.json program that lists the your projects dependencies
• specifies versions of packages
• makes your build reproducible, to share with other devs

(directory with one or more files, and a package.json file)

Question 10

How can you create a package.json with npm?

Answer 10

use the npm init command in the root directory of package

Question 11

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

Answer 11

packages that your project depends on,

you can list them as “dependencies” in package.json

Question 12

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

Answer 12

the project will install all listed dependencies with the install command

Question 13

How do you add express to your package dependencies?

Answer 13

it will be added when you use npm install express

Question 14

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

Answer 14

listen()

Question 15

How do you mount a middleware with an Express application?

Answer 15

app.use() / app.METHOD() ?

Question 16

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

Answer 16

req, and res

Question 17

What is the purpose of the Content-Type header in HTTP request and response messages?

Answer 17

.

Question 18

What does express.static() return?

Answer 18

serveStatic function

Question 19

What is the local __dirname variable in a Node.js module?

Answer 19

absolute path to the current module

Question 20

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

Answer 20

combines multiple strings into a directory path format

Question 21

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

Answer 21

application/json

Question 22

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

Answer 22

parses incoming json requests, and creates an empty body(object) - req.body

Question 23

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

Answer 23

just syntax, to give user control