Node.js

Question 1

What is Node.js

Answer 1

Node.js is a program that allows JavaScript to be run outside of a web browser.

Question 2

What can Node.js be used for?

Answer 2

It is commonly used to build back ends for Web apps, command-line programs, or any kind of automation that developers wish to perform.

Question 3

What is REPL?

Answer 3

Read-Eval-Print Loop

Question 4

When was Node.js created?

Answer 4

2009 by Ryan Dahl

Question 5

What other back end languages have you heard of?

Answer 5

Ruby, PHP, Java, c#, Python, C, C++, Swift (Not common for back end though feasible), Objective C (not common for back end though feasible), JavaScript, Perl, Go, Erlang, Elixir.

Question 6

What is CLI?

Answer 6

Command Line Interface

Question 7

What is GUI?

Answer 7

Graphical User Interface

Question 8

Give at least one use case for each command listed in this exercise:
man
cat
ls
pwd
echo
touch
mkdir
mv
rm
cp

Answer 8

man: Look up manuals
cat: Concatenate files and print on the standard output.
ls: list items in the directory.
pwd: print name of current/working directory.
echo: Display a line of text
touch: Make new files or update timestamps.
mkdir: Makes new directories
mv: Move (rename) files
rm: Remove files or directories.
cp: Copy files or directories.

Question 9

What are the three virtues of a great programmer?

Answer 9

impatience, laziness, hubris.

Question 10

What is a computer process?

Answer 10

The instance of a computer program that is being executed by one or many threads. It contains the program code and its activity.

Question 11

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

Answer 11

300

101 Windows Processes
98 Background Processes
11 Apps

Question 12

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

Answer 12

Because we are making multiple processes work together to form one application.

Question 13

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

Answer 13

It is a global that provides information about, and control over, the current Node.js process. As a global, it is always available to Node.js applications without using require().

It is also an instance of EventEmitter.

Question 14

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

Answer 14

node command then process

Question 15

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

Answer 15

An array of strings

Question 16

What is a JavaScript Module?

Answer 16

It is a single .js file

Question 17

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

Answer 17

\_\_dirname
\_\_filename
exports
module
require()

Question 18

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

Answer 18

clear immediate function
setInterval
setTimeout
process
global

Question 19

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

Answer 19

export the data inside the file to another module.

Question 20

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

Answer 20

assign require(‘./filename’); to a new variable. const banana = require(./banana);

Question 21

What is the JavaScript Event Loop?

Answer 21

A loop that checks the stack and the task queue and pushes the task queue onto the stack once its clear.

Question 22

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

Answer 22

Blocking clogs up the stack and prevents anything else from happening until that code is done running. Non-blocking pushes code into the api then into the task queue to be run once it’s completed its processing leaving the user with the ability to continue working.

Question 23

What is a directory?

Answer 23

A folder which allows users to group files into separate containers.

Question 24

What is a relative file path?

Answer 24

A location that is relative to a current directory. Also known as a folder.

Question 25

What is an absolute file path?

Answer 25

An absolute file path always contains the root (/) element and the complete directory list required to locate the file.

Question 26

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

Answer 26

fs

Question 27

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

Answer 27

fs.writeFile

Question 28

Are file operations using the fs module synchronous or asynchronous?

Answer 28

Both.