Node.js

Question 1

What is Node.js?

Answer 1

Node.js is an open-source, cross-platform, back-end JavaScript runtime environment that runs on the V8 engine and executes JavaScript code outside a web browser.

Question 2

What can Node.js be used for?

Answer 2

Node.js is primarily used for non-blocking, event-driven servers, due to its single-threaded nature. It’s used for traditional web sites and back-end API services, but was designed with real-time, push-based architectures in mind.

Question 3

What is a REPL?

Answer 3

provides a Read-Eval-Print-Loop (REPL) implementation that is available both as a standalone program or includible in other applications.

Question 4

When was Node.js created?

Answer 4

May 27, 2009

Question 5

What back end languages have you heard of?

Answer 5

python, c, c++, java, ruby, php

Question 6

What is a computer process?

Answer 6

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

Question 7

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

Answer 7

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

Question 8

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

Answer 8

The process object is a global that provides information about, and control over, the current Node.js process.

Question 9

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

Answer 9

As a global, it is always available to Node.js applications without using require(). It can also be explicitly accessed using require():
const process = require('process');

Question 10

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

Answer 10

array

Question 11

What is a JavaScript module?

Answer 11

In the Node.js module system, each file is treated as a separate module.

Question 12

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

Answer 12

__dirname, __filname, exports, module, require()

Question 13

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

Answer 13

console, process

Question 14

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

Answer 14

Module exports are the instruction that tells Node.js which bits of code (functions, objects, strings, etc.) to “export” from a given file so other files are allowed to access the exported code.

Question 15

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

Answer 15

require

Question 16

What is the JavaScript Event Loop?

Answer 16

event loop pushes anything that is queued to the callstack if it is empty

Question 17

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

Answer 17

blocking is code that is slow

Question 18

What is a directory?

Answer 18

a folder that contains other directories and files

Question 19

What is a relative file path?

Answer 19

The path with reference to current directory is called relative

Question 20

What is an absolute file path?

Answer 20

An absolute import path is a path that starts from a root, and you need to define a root first

Question 21

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

Answer 21

fs module

Question 22

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

Answer 22

fs.writeFile( )

Question 23

Are file operations using the fs module synchronous or asynchronous?

Answer 23

both