nodejs

Question 1

What is Node.js?

Answer 1

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

executing javascript code outside of the web browser

Question 3

What is a REPL?

Answer 3

read-eval-print loop and basically provides a programmer with an interactive programming environment

Question 4

When was Node.js created?

Answer 4

May 27, 2009

Question 5

What back end languages have you heard of?

Answer 5

node.js

Question 6

What is a computer process?

Answer 6

instance of a computer program being executed 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

529 processes, 2079` threads

Question 8

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

Answer 8

web dev is based on making multiple processes work together to form one application

Question 9

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

Answer 9

global object that provides 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 object or using require, i.e.,

the process object itself:
console.log(process)

or

assigning a variable to the require method of the object:
const process = require('process')
console.log(process)

Question 11

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

Answer 11

string

Question 12

What is a JavaScript module?

Answer 12

a single js file, i.e., splitting JavaScript programs up into separate “modules” that can be imported when needed

Question 13

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

Answer 13

Variables local to the module will be private, because the module is wrapped in a function by Node.js (see module wrapper)

filename, dirname

Question 14

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

Answer 14

exports, require

Question 15

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

Answer 15

exports a file, i.e.,

module.exports.hello = () => { return ‘hello’; }

Question 16

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

Answer 16

using the require keyword, i.e.,

require(‘./name-of-that-is-using-module-exports’)

Question 17

What is a directory?

Answer 17

collection of folders, files, etc

technically a “folder”

Question 18

What is a relative file path?

Answer 18

local file path, i.e.,

./assets/images/hi.jpeg

linking to something on the same server

Question 19

What is an absolute file path?

Answer 19

global file path, i.e.,

a domain (https://google.com)

usually has a protocol before like ‘http’, ‘https’. ‘ftp’, ‘file’

linking to something on a different server

Question 20

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

Answer 20

fs/promises API which provides asynchronous file system methods that return promises

Question 21

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

Answer 21

fs.writeFile

Question 22

Are file operations using the fs module synchronous or asynchronous?

Answer 22

depends; the fs module itself has options to perform a given task async (usually denoted by callback functions and the lack of the sync keyword) or sync (usually denoted by the ‘sync’ keyword, i.e., syncaccess, writefilesync)

sync blocks the event loop saying perform this task first before anything else; makes the cpu wait

async is performant

aka The fs module is unique compared with other I/O modules (like net and http) in that it has both asynchronous and synchronous APIs - means that it provides a mechanism to perform blocking I/O