Node.js

Question 1

[Command Line]
What is a CLI?

Answer 1

Command line interface - interface for commands

Question 2

[Command Line]
What is GUI?

Answer 2

graphical user interface - applications meant for consumers (end users)

Question 3

[Node intro]
What is Node.js?

Answer 3

A program that allows JavaScript to be run outside of a web browser used to build back ends for Web applications, command-line programs or any kind of automation that developers wish to perform.

Question 4

[Node Intro]
What can Node.js be used for?

Answer 4

To build scalable network applications, using JavaScript in back-end

Question 5

[Node Intro]
What is a REPL?

Answer 5

Read-Eval-Print-Loop
Reads input, evaluates, prints the output, waits for next input (loop)

Question 6

[Node Intro]
When was Node.js created?

Answer 6

May 27, 2009

Question 7

[Node Intro]
What back end languages have you heard of?

Answer 7

Scripting Languages (interpreted): Python, JavaScript, Ruby, PHP, Perl

Compiled Languages: C, C++, Go, haskell, crystal, rust, SQL* (databases)

Partially Compiled: Java (jvm), Scala (jvm), Clojure (jvm), Kotlin (jvm), C# (.net clr), F# (.net clr), visual basic

Question 8

[Node Process Argv]
What is the process object in a Node.js program?

Answer 8

It gives information and control over the current node.js process.

Question 9

[Node Process Argv]
How do you access the process object in a Node.js program?

Answer 9

use require() or
call the process variable because it’s global

Question 10

[Node Process Argv]
What is the data type of process.argv in Node.js?

Answer 10

An array of strings containing all arguments passed when command was launched

Question 11

[Node Module System]
What is a JavaScript module?

Answer 11

Separate JavaScript files for different specific functionalities, that can work together with other files (modules).

Question 12

[Node Module System]
What values are passed into a Node.js module’s local scope?

Answer 12

__dirname
__filename
exports
module
require()

Question 13

[Node Module System]
Give two examples of truly global variables in a Node.js program.

Answer 13

process
console
setInterval() /clearInterval()
setTimeOut() / clearTimeOut()

Question 14

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

Answer 14

So that modules can share functionalities between files.

Question 15

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

Answer 15

require(‘relativePathURL’);
example: require(‘./filename.js’);

Question 16

[Node the Event Loop]
What is the JavaScript Event Loop?

Answer 16

The event loop monitors the call stack, when the call stack is empty it checks the if queue is empty. If there is something in the queue, it will push it to the call stack.

Question 17

[Node the Event Loop]
What is the difference between ‘blocking’ and ‘non-blocking’ with respect to how code is executed?

Answer 17

Blocking is if something is currently occupying the call stack, it is blocking until it is finished. If something is being executed off the call stack, it is non-blocking. When it’s done, then it event loop pushes it to the call stack.

Question 18

[Node fs Readfile]
What is a directory?

Answer 18

a ‘folder’ or location which points to other directories or files

Question 19

[Node fs Readfile]
What is a relative file path?

Answer 19

A path pointing to another local file (from where we currently are)

Question 20

[Node fs Readfile]
What is an absolute file path?

Answer 20

Points to a file starting from the root

Question 21

[Node fs Readfile]
What module does Node.js include for manipulating the file system?

Answer 21

fs module

Question 22

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

Answer 22

.writeFile()

Question 23

[Node fs Writefile]
Are file operations using the fs module synchronous or asynchronous?

Answer 23

both, there are forms for both
for blocking, use sync method
for non-blocking, remove sync

Question 24

[Webpack-intro]
What is Webpack?

Answer 24

module bundler
looks at entry file and all required files and bundles them

Question 25

[Webpack intro]
How do you add a devDependency to a package?

Answer 25

npm install –save-dev package-name

Question 26

[Webpack Intro]
What is an NPM script?

Answer 26

a name for a terminal command that can be customized by editing in package.json

Question 27

[Webpack Intro]
How do you execute Webpack with npm run?

Answer 27

$ npm run webpack

Question 28

What is the ‘$ cd’ command for?

Answer 28

cd - changes directory

Question 29

What is the ‘$ man’ command for?

Answer 29

man - opens manual for commands

Question 30

What is the ‘$ cat’ command for?

Answer 30

cat - concatenates files and prints file content

Question 31

What is the ‘$ ls’ command for?

Answer 31

ls - lists current directory’s contents

Question 32

What is the ‘$ pwd’ command for?

Answer 32

pwd - prints name of current/working directory

Question 33

What is the ‘$ echo’ command for?

Answer 33

echo - displays line of text

Question 34

What is the ‘$ touch’ command for?

Answer 34

touch - change file timestamps

Question 35

What is the ‘$ mkdir’ command for?

Answer 35

mkdir - creates new directory

Question 36

What is the ‘$ mv’ command for?

Answer 36

mv - moves and renames files

Example:
1. a.txt and b.txt exist
$ mv a.txt b.txt
deletes a.txt and puts all of its content in b.txt

2. a.txt exists
   $ mv a.txt new.txt
   renames a.txt to new.txt

Question 37

What is the ‘$ rm’ command for?

Answer 37

rm - removes file or directory

Question 38

What is the ‘$ cp’ command for?

Answer 38

cp - copies files and directories