Node.js

Question 1

What is Node.js?

Answer 1

a JavaScript runtime build on Chrome’s V8 JavaScript engine

Question 2

What can Node.js be used for?

Answer 2

its used for backend and command line scripts

Question 3

What is a REPL?

Answer 3

Read, Evaluate, Print, Loop

Question 4

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

Answer 4

The process object is a global that provides information about, and control over, the current Node.js process

Question 5

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

Answer 5

reference it

Question 6

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

Answer 6

Array of strings

Question 7

What is a JavaScript module?

Answer 7

a file that contains related code

Question 8

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

Answer 8

exports, require, filename, dirname

Question 9

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

Answer 9

process, global

Question 10

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

Answer 10

To export a piece of code so other files are able to access it

Question 11

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

Answer 11

you add module.exports to whatever code you want to export and then require method to where you want to use it

Question 12

What is the JavaScript Event Loop?

Answer 12

a runtime model that is responsible for executing code, collecting and processing events and executing queued sub-tasks.

Question 13

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

Answer 13

Blocking refers to operations that block further execution until that operation finishes while non-blocking refers to code that doesn’t block execution.

Question 14

What is a directory?

Answer 14

A special file that lists other files and directories

Question 15

What is a relative file path?

Answer 15

relative file path tells you how to get to a file from your current location

Question 16

What is an absolute file path?

Answer 16

location of a file from the root directory

Question 17

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

Answer 17

fs

Question 18

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

Answer 18

writeFile

Question 19

What is NPM?

Answer 19

npm is a registry that contains code packages

Question 20

What is a package?

Answer 20

a file or directory that is described by a package.json file

Question 21

How can you create a package.json with npm?

Answer 21

npm init

Question 22

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

Answer 22

a dependency is something that your package depends on and to add one use npm install

Question 23

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

Answer 23

it updates your package json and downloads the package from the npm registry

Question 24

How do you add express to your package dependencies?

Answer 24

npm install express –save

Question 25

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

Answer 25

listen

Question 26

How do you mount a middleware with an Express application?

Answer 26

use method

Question 27

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

Answer 27

request and response

Question 28

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

Answer 28

appication/json

Question 29

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

Answer 29

This method is used to parse the incoming requests with JSON body and is based upon the bodyparser. You would need it when you want to receive JSON data and add it to a data model

Question 30

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

Answer 30

it defines the action to be performed

Question 31

What does express.static() return?

Answer 31

it returns a path

Question 32

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

Answer 32

The directory name of the current module

Question 33

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

Answer 33

The path.join() method joins all given path segments together using the platform-specific separator as a delimiter, then normalizes the resulting path.