Node.js

Question 1

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

Answer 1

section of code enclosed within { }, ex: function, conditional, loop

Question 2

What is a CLI?

Answer 2

command-line interface, text-based

Question 3

What is a GUI?

Answer 3

graphical-user interface, graphical icon-based

Question 4

man

Answer 4

user manual for commands

Question 5

cat

Answer 5

combine content of files

Question 6

ls

Answer 6

shows content of directory

Question 7

pwd

Answer 7

shows current directory

Question 8

echo

Answer 8

prints out text on terminal, like console.log( )

Question 9

touch

Answer 9

changes file timestamps, can be used to create a new file

Question 10

mkdir

Answer 10

creates a new directory

Question 11

mv

Answer 11

renames or moves a file

Question 12

rm

Answer 12

deletes a file

Question 13

cp

Answer 13

copies a file

Question 14

What are the three virtues of a great programmer?

Answer 14

laziness, impatience, hubris

Question 15

What is Node.js?

Answer 15

a program that allows JS to be run outside of a web browser

Question 16

What can Node.js be used for?

Answer 16

it can be used for back-ends for Web applications, command-line programs anything with automation

Question 17

What is a REPL?

Answer 17

read-eval-print loop

Question 18

When was Node.js created?

Answer 18

May 27, 2009

Question 19

What is a computer process?

Answer 19

a process is the instance of a computer program that is being executed by one or many threads

Question 20

Roughly how many computer processes are running on your host operating system (Task Manager or Activity Monitor)?

Answer 20

480 processes

Question 21

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

Answer 21

Full stack Web development is based on making multiple processes work together to form one application, so having at least a cursory awareness of computer processes is necessary

Question 22

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

Answer 22

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

Question 23

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

Answer 23

with or without require( )

Question 24

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

Answer 24

an array of strings of the command-line arguments

Question 25

What is a JavaScript module?

Answer 25

a single .js file

Question 26

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

Answer 26

module, exports, require( ), __dirname, __filename

Question 27

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

Answer 27

process, global

Question 28

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

Answer 28

allows you to export functions and objects from a module to be used in another

Question 29

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

Answer 29

require( relative path to file)

Question 30

What is the JavaScript Event Loop?

Answer 30

the event loop looks at the call stack and the task queue; if the stack is empty, the event loop pushes the first thing on the queue into the stack

Question 31

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

Answer 31

blocking means the code is occupying the call stack, non-blocking means the code is a Web API (network, DOM, events) and is pushed to the task queue

Question 32

What is a directory?

Answer 32

a collection of files

Question 33

What is a relative file path?

Answer 33

points to a file within the context of the current directory

Question 34

What is an absolute file path?

Answer 34

points to a file from the root directory

Question 35

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

Answer 35

fs

Question 36

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

Answer 36

.writeFile( )

Question 37

Are file operations using the fs module synchronous or asynchronous?

Answer 37

both

Question 38

What is NPM?

Answer 38

website, CLI, registry that provides a way to reuse code from other developers, to share your code with them, and manage different versions of code

Question 39

What is a package?

Answer 39

a directory containing a program described by a package.json file, and a package.json file

Question 40

How can you create a package.json with npm?

Answer 40

npm init –yes

Question 41

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

Answer 41

another package a package needs in order to work, npm install

Question 42

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

Answer 42

package.json will be updated to include the dependency and the package for the dependency will be installed to the node_modules directory

Question 43

How do you add express to your package dependencies?

Answer 43

npm install express

Question 44

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

Answer 44

app.listen( )

Question 45

How do you mount a middleware with an Express application?

Answer 45

app.use( )

Question 46

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

Answer 46

req and res

Question 47

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

Answer 47

application/json

Question 48

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

Answer 48

returns a middleware function that parses JSON, attaches data to the body property of the req object, used when expecting requests with JSON

Question 49

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

Answer 49

describes the action the server has to perform

Question 50

What does express.static( ) return?

Answer 50

middleware function that serves files within a given root directory

Question 51

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

Answer 51

absolute file path of directory of current module

Question 52

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

Answer 52

join all given path segments