Node.js / NPM

Question 1

What is Node.js?

Answer 1

Node.js is a JavaScript runtime environment that executes JS code outside web browsers.

Question 2

What can Node.js be used for?

Answer 2

Node.js is used for backend operations in JavaScript.

Question 3

What is a REPL?

Answer 3

A Read-Eval-Print-Loop is a command-line tool for processing expressions.

Question 4

What is a computer process?

Answer 4

An instance of a computer program being executed by one or many threads.

Question 5

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

Answer 5

At least 200.

Question 6

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

Answer 6

It is an important concept in apps made up of multiple components such as clients, servers, and databases.

Question 7

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

Answer 7

An object that represents the current instance of the node process being run.

Question 8

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

Answer 8

process exists as a global variable.

Question 9

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

Answer 9

Array of strings.

Question 10

What is a JavaScript module?

Answer 10

single .js file with a standalone function.

Question 11

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

Answer 11

exports, require, module, __filename, __dirname

Question 12

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

Answer 12

process, global

Question 13

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

Answer 13

module.exports contains data that can be imported into other modules.

Question 14

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

Answer 14

const func = require(‘./func’);

Question 15

What is the JavaScript Event Loop?

Answer 15

A design pattern that loops through the call stack and the callback queue, checking if the stack is empty and pushing functions onto it from the queue if it is.

Question 16

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

Answer 16

Blocking calls block further execution of functions in the stack until they return whereas non-blocking calls do not.

Question 17

What is NPM?

Answer 17

Node Package Manager, made up of a website, a command-line interface, and a registry of software packages. The CLI installs and updates packages.

Question 18

What is a package?

Answer 18

One or more modules grouped together.

Question 19

How can you create a package.json with npm?

Answer 19

Navigate to root directory of package and execute “npm init [–yes]”.

Question 20

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

Answer 20

A dependency is a package needed to run another package. They are added by the command “npm install package-name [–save-prod]”.

Question 21

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

Answer 21

When another user runs “npm install”, npm will install the dependencies listed in package.json.

Question 22

What is a directory?

Answer 22

A file system cataloguing structure that contains references to other computer files and directories.

Question 23

What is a relative file path?

Answer 23

A file path relative to the current directory.

Question 24

What is an absolute file path?

Answer 24

A file path beginning from the root.

Question 25

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

Answer 25

The fs module.

Question 26

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

Answer 26

.writeFile()

Question 27

Are file operations using the fs module synchronous or asynchronous?

Answer 27

fs has both synchronous and asynchronous versions of operations.