This document provides an introduction to Node.js, including what it is, what it is good for, its core modules, and some basic JavaScript concepts. Node.js is an evented I/O JavaScript runtime built on V8 that uses an asynchronous and non-blocking I/O model. It is lightweight and good for building networked applications, streaming data, and event-driven real-time apps. Its core modules include HTTP, TCP, DNS, filesystems, and crypto. The document also covers JavaScript types, functions, closures, classes, and try/catch blocks.

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Intro to NodeJS

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What is Node.JS?
● Evented I/O
● V8 Javascript
● Asynchronous I/O
● Highly concurrent

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What is NodeJS good for?
● Lightweight, networked apps
● Proxies with embedded logic
● Streaming data
● System Scripting
● Evented realtime apps
● Non Blocking I/O: DB, Filesystems

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Core Modules
● HTTP/HTTPS
● TCP
● DNS
● Filesystems
● Crypto, SSL/TLS, Readline, etc..

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Basic Javascript
Types :
❏ primitive are number, boolean, string, null
and undefined
❏ complex are array, function and object
// primitives
var a = 5;
var b = a;
b = 6;
a; // will be 5
b; // will be 6
// complex
var a = [‘hello’, ‘world’];
var b = a;
b[0] = ‘bye’;
a[0]; // will be ’bye’
b[0]; // will be ‘bye’

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Basic Javascript
Function :
❏ Most importance
❏ When function call this is the global
object
❏ On browser global object == windows
var a = function () {}
console.log(a);
var a = function a () {
‘function’ == typeof a; // true
};

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Basic Javascript
Closure :
❏ Every time a function is called, a new
scope is define
❏ Variables defined within
a scope are accessible only
to that scope and
inner scopes
var a = 5;
function woot () {
a == 5; // true
var a = 6;
function test () {
a == 6; // true
}
test();
};
woot();

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Basic Javascript
Classes :
❏ No class keyword. A class define like
function
function Animal (name) {
this.name = name;
}
Animal.prototype.getName () {
return this.name;
};
var animal = new Animal(‘tobi’);
a.getName() == ‘tobi’; // true

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Basic Javascript
try {} catch {} :
❏ allow to capture an exception
function () {
var a = 5;
try {
a();
} catch (e) {
e instanceof Error; // true
}
console.log(‘you got here!’);
}

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Non blocking I/O
Global Object
Modules
Events