Node.js

Question 1

What is Node.js?

Answer 1

An asynchronous event-driven JavaScript runtime, 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

Build back ends for Web applications, command-line programs, or any kind of automation

Question 3

What is a REPL?

Answer 3

A Read-Eval-Print-Loop (REPL) reads input from the user, executes them, and returns the result to the user.

Question 4

When was Node.js created?

Answer 4

2009

Question 5

What back end languages have you heard of?

Answer 5

PHP, Ruby on Rails, C#, Java

Question 6

What is a computer process?

Answer 6

The execution of code/program/application by one or more threads

Question 7

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

Answer 7

hundreds

Question 8

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

Answer 8

Full stack is made up of many modules. To track the status of the server, check its pid.

Question 9

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

Answer 9

Global variable with information about and control over the current Node.js process.

Question 10

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

Answer 10

process variable

Question 11

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

Answer 11

Array of strings

Question 12

What is a JavaScript module?

Answer 12

JavaScript file

Question 13

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

Answer 13

dirname, filename, exports, required

Question 14

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

Answer 14

process, argv, console

Question 15

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

Answer 15

Allows you to write modular code and easily reuse it by importing and exporting.

Question 16

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

Answer 16

Use require.

Question 17

What is a directory?

Answer 17

A node in the file system that contains other files and directories.

Question 18

What is a relative file path?

Answer 18

A path with . or .. to indicate current dir and parent dir respectively.

Question 19

What is an absolute file path?

Answer 19

A path with the all parent dirs from the root down.

Question 20

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

Answer 20

fs

Question 21

How do you add express to your package dependencies?

Answer 21

npm install

Question 22

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

Answer 22

listen

Question 23

How do you mount a middleware with an Express application?

Answer 23

Use a middleware method: use(), get(), post(), put(), delete()

Question 24

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

Answer 24

req, res, and next

Question 25

What is NPM?

Answer 25

the website, command line interface, and registry

Question 26

What is a package?

Answer 26

Module that has been added to npm’s registry

Question 27

How can you create a package.json with npm?

Answer 27

npm init

Question 28

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

Answer 28

A package the module uses or needs. npm install

Question 29

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

Answer 29

Adds dependency to node module dir. Adds it to package.json.

Question 30

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

Answer 30

application/json; charset=utf-8

Question 31

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

Answer 31

Parses http request body from JSON to an object. Needed when you expect a JSON string in a http post request

Question 32

What is Webpack?

Answer 32

Webpack bundles together JS modules into one file to prevent a network bottleneck that could occur when loading multiple files. Webpack uses Immediately invoked function expressions (IIFE) to concatenate files without scope collision.

Question 33

How do you add a devDependency to a package?

Answer 33

Install dependency and check that it shows up in package.json under dependencies.

Question 34

What is an NPM script?

Answer 34

NPM supports a number of built-in scripts. To use, list them in your package.json under scripts and call NPM build on them.

Question 35

How do you execute Webpack with npm run?

Answer 35

Insert a “build” property under scripts in package.json. Run “npm run build”.

Question 36

What does express.static() return?

Answer 36

Middleware function that serves static files

Question 37

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

Answer 37

Path of the current JavaScript file’s directory.

Question 38

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

Answer 38

Concatenates the two args, which should represent paths and directory names

Question 39

What does fetch() return?

Answer 39

a promise

Question 40

What is the default request method used by fetch()?

Answer 40

GET

Question 41

How do you specify the request method (GET, POST, etc.) when calling fetch?

Answer 41

{ method: }