Technology

NodeJS

Jacques Leemans
, , ,
4 min. read

NodeJs is a Runtime Environment

Introduction

NodeJS is a JavaScript runtime environment, which runs on Google’s V8, mostly for running JavaScript on the backend server. Technically NodeJs is a wrapper around the Google V8 Virtual Machine.

NodeJs uses non-blocking or Asynchronous API’s

Single Threaded using an Event Queue, Node continuously monitors this queue, if the event is ready, it takes it out and processes it.

Node is ideal for IO based process (like file access, database access)

Node is not ideal for CPU intensive features like video encoding.

NodeJs

In node the global object is global
Global Objects https://nodejs.org/api/globals.html
Process Object https://nodejs.org/api/process.html

Microservices
https://medium.com/@cramirez92/build-a-nodejs-cinema-microservice-and-deploying-it-with-docker-part-1-7e28e25bfa8b

Frameworks:
http://nodeframework.com/

RESTful API development:
http://apiworkbench.com/docs/

Installing Node

https://nodejs.org/en/

Or use Node Version Manager
https://github.com/nvm-sh/nvm

Packages

NPM - Node Package Manager
Uses Semantic Versioning (SemVer)

~1.2.3 is the same as 1.2.X
^1.2.3 is the same as 1.X.X

https://semver.npmjs.com/

NVM - Node Version Manager

Built-in Modules

File-system (fs)
Http
Crypto
Zip

In Node, window is global, for example, global.console.log();

Variables are added to the global scope

Os
Fs
Events
Http

Timer Functions

Global objects:

setTimeout()
clearTimeout()
setInterval()
clearInterval()

Modules

Every file in Node is considered a module

Variables and functions are scoped to the module, thus private by default.

You can load modules in a few different ways.

Common NodeJS Module:

1
const http = require(‘http’);

ECMAScript Module:

Rename file to .mjs, then:

1
import http from ‘http’;

Or, using named imports, for example:

1
import { createServer } from ‘http’;

Modes

You can run NodeJS is a few different modes.

REPL Mode

Read
Eval
Print
Loop

Start by typing:

1
node

In a terminal window

Common REPL commands

.help
.break
.clear
.editor
.load
.save
.exit (or CTRL + D)

Double tap TAB, to show more information about global, and/or objects.

For example, pressing double tab on an empty line, will return:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
Array                 ArrayBuffer           Atomics
BigInt                BigInt64Array         BigUint64Array
Boolean               Buffer                DataView
Date                  Error                 EvalError
FinalizationRegistry  Float32Array          Float64Array
Function              Infinity              Int16Array
Int32Array            Int8Array             Intl
JSON                  Map                   Math
NaN                   Number                Object
Promise               Proxy                 RangeError
ReferenceError        Reflect               RegExp
Set                   SharedArrayBuffer     String
Symbol                SyntaxError           TextDecoder
TextEncoder           TypeError             URIError
URL                   URLSearchParams       Uint16Array
Uint32Array           Uint8Array            Uint8ClampedArray
WeakMap               WeakRef               WeakSet
WebAssembly           _                     _error
assert                async_hooks           buffer
child_process         clearImmediate        clearInterval
clearTimeout          cluster               console
constants             crypto                decodeURI
decodeURIComponent    dgram                 dns
domain                encodeURI             encodeURIComponent
escape                eval                  events
fs                    global                globalThis
http                  http2                 https
inspector             isFinite              isNaN
module                net                   os
parseFloat            parseInt              path
perf_hooks            process               punycode
querystring           queueMicrotask        readline
repl                  require               setImmediate
setInterval           setTimeout            stream
string_decoder        sys                   timers
tls                   trace_events          tty
undefined             unescape              url
util                  v8                    vm
wasi                  worker_threads        zlib

__defineGetter__      __defineSetter__      __lookupGetter__
__lookupSetter__      __proto__             hasOwnProperty
isPrototypeOf         propertyIsEnumerable  toLocaleString
toString              valueOf

constructor

CLI Mode

1
node

Code Snippets

HTTP Web Server

If you need to create a simple web-server, without using ExpressJS, create a new script, with content:

1
2
3
4
5
6
7
8
9
const http = require(‘http’);

const server = http.createServer((req, res) => {
res.end(‘CONTENT’);
});

server.listen(3000,()=>{
console.log(‘Server Running on port 3000’);
});

Deployment

NodeJS can be deployed to:

Functions-as-a-Service

Firebase Functions
AWS Lamba

Server

Heroku
AWS
GCP
Azure

Courses

https://nodejs.dev/learn/introduction-to-nodejs

Working With Node.js

Node.js: Getting Started

Udemy Courses

https://academy.zenva.com/course/node-js-and-express-for-game-development/

References

Global Objects
Process Object
Microservices
Frameworks
RESTful API development
Hosting
NodeJS is not a framework
Why Node
Samer Buna

Share