Node.js

Question 1

What are the 3 components of a fullstack Web architecture?

Answer 1

1. A front-end web server serving static content, and potentially some cached dynamic content. In web-based application, front end is the content rendered by the browser. The content may be static or generated dynamically.
2. A middle dynamic content processing and generation level application server (e.g., Symfony, Spring, ASP.NET, Django, Rails, Node.js).
3. A back-end database or data store, comprising both data sets and the database management system software that manages and provides access to the data.

Question 2

What is Node.js?

Answer 2

An asynchronous event-driven JavaScript runtime for backend servers that things talk to.

Question 3

What can Node.js be used for?

Answer 3

Run applications on the backend. Servers.

Question 4

What is a REPL?

Answer 4

Read–eval–print loop. It is a simple interactive computer programming environment that takes single user inputs, executes them, and returns the result to the user; a program written in a REPL environment is executed piecewise.

Question 5

When was Node.js created?

Answer 5

May 27, 2009

Question 6

What backend languages have you heard of?

Answer 6

PHP, Ruby, C++, Java, C#

Question 7

What is a computer process?

Answer 7

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

Question 8

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

Answer 8

105

Question 9

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

Answer 9

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. This will be extremely important when learning about applications made of multiple components, such as clients, servers, and databases.

Question 10

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

Answer 10

The process object 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 can also be explicitly accessed using require(). The process object is also an instance of EventEmitter.

Question 11

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

Answer 11

Just call or use the variable since it is global and always available.

Question 12

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

Answer 12

Object data type of an array. The elements in the array are always turned to strings.

Question 13

How do you access the command line arguments in a Node.js program?

Answer 13

Destructure process.argv and take everything starting at index 2.

Question 14

What is a JavaScript module?

Answer 14

A file that has JavaScript in it.

Question 15

What are the advantages of modular programming?

Answer 15

Break down code into smaller chunks and be more organized.

Question 16

In JavaScript, how do you make a function in a module available to other modules?

Answer 16

Export it so that other modules can import it.

Question 17

In JavaScript, how do you use a function from another module?

Answer 17

Import it then call it.

Question 18

What is the JavaScript Event Loop?

Answer 18

It looks at the stack and looks at the task queue, if the stack is empty/clear it takes the first thing in the task queue and pushes it onto the stack, which effectively runs it.

Question 19

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

Answer 19

Blocking is synchronous code that “blocks” the call stack which makes other things not able to run while it is executing while Non-Blocking is asynchronous code that is pushed to the task queue and runs when the stack is empty/clear, so it doesn’t hog the stack and block or lock the browser.

Question 20

What is a directory?

Answer 20

It is a folder or container that holds files or other directories.

Question 21

What is a relative file path?

Answer 21

A relative file path starts at the current working directory.

Question 22

What is an absolute file path?

Answer 22

An absolute file path always starts at the root. It always starts with a /

Question 23

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

Answer 23

The File System module.

Question 24

What method is available in the node:fs module for reading data from a file?

Answer 24

The readFile method.

Question 25

What method is available in the node:fs module for writing data to a file?

Answer 25

The writeFile method.

Question 26

Are file operations using the fs module synchronous or asynchronous?

Answer 26

They are asynchronous.

Question 27

What is NPM?

Answer 27

Node Package Manager. npm is the world’s largest software registry. Open source developers from every continent use npm to share and borrow packages, and many organizations use npm to manage private development as well.
npm consists of three distinct components: the website, the Command Line Interface (CLI), the registry.

Question 28

What is a package?

Answer 28

Bits of reuseable code, a directory with one or more files in it. Also called a module. Usually has the .js file and a package.json file which contains some metadata about the package.

Question 29

How can you create a package.json with npm?

Answer 29

On the CLI, navigate to the root directory of the package wit cd /path/to/package then run the command ‘npm init –yes’.

Question 30

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

Answer 30

It is any packages that a package depends on. You add one to a package by using the npm install command.

Question 31

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

Answer 31

The package.json file will denote that the package(s) are dependencies and a node_modules directory will be created in the root directory of the package, which will then download all packages it depends on recursively.

Question 32

What are some other popular package managers?

Answer 32

The most popular is Yarn, developed by Facebook (which also develops React and Jest). Another lightweight competitor gaining popularity is PNPM.

Question 33

What is a version?

Answer 33

SEMVER. three numbers. a.b.c the first letter is the major version. It changes whenever the package makes a breaking change. The second number is the minor version. It changes when they add functionality to the package in a backwards compatible way. The last letter is called the bugfix version. It changes if they fixed a bug.