JavaScript Objects

Who I’m
● My name is Hazem Hagrass
● Lead Software Engineer @BADR, joined BADR @2010
● Contacts:
○ website
○ hazem.hagrass@badrit.com
○ Linkedin

Introduction
● JavaScript is object-oriented language.
● Not really object-oriented language.
● There are multiple ways to do OOP in JS.
● There are 5 primitives only in JS: Number, String,
Boolean, undefined, null.
● Everything else is an Object.

User Defined Objects
● All user-defined objects and built-in objects are
descendants of an object called Object.
var employee = new Object();
employee.name = “Hazem Hagrass”;
var books = new Array("C++", "Perl", "Java");
var day = new Date("August 15, 1947");

User Defined Objects
● new Object() produces an empty container of
name/value pairs.
● Its nature like hash but no hash codes or rehash codes
are available.

Objects with a User-Defined Function
● Functions are first-class citizens in JS, they can
contain number of methods, so functions are objects
that can contain variables and methods.
● this keyword is used to refer to the object that has
been passed to a function.
function employee(name, departement){
this.name = name;
this.departement = departement;
}
var emp = new employee(“Hazem Hagrass”, “IT”);

Object Methods
function initSalary(amount){
this.salary = amount;
}
function employee(name, departement){
this.name = name;
this.departement = departement;
this.salary = 0;
this.doWork = function(){}
this.initSalary = initSalary;
}

Object Literal
● Object literals encapsulate data, enclosing it in a tidy
package.
● This minimizes the use of global variables which can
cause problems when combining code.
var Coor = {
x: 0,
y: 0
}
console.log(coor.x);

Object Literal
var BannerRotator = {
banners: ["smile.gif", "frown.gif", "bomb.gif"],
index: 0,
getNextBanner: function() {
BannerRotator.index ++;
BannerRotator.index = BannerRotator.index %
BannerRotator.banners.length;
var banner = BannerRotator.banners[BannerRotator.
index];
return banner;
}
};

Why Object Literal?
● Object literals enable us to write code that supports
lots of features yet still provide a relatively
straightforward process for implementers of our code.
● No need to invoke constructors directly or maintain
the correct order of arguments passed to functions.
● Object literals are also useful for unobtrusive event
handling; they can hold the data that would otherwise
be passed in function calls from HTML event handler
attributes.

JavaScript Objects

In this document

More Related Content

What's hot

Viewers also liked

Similar to JavaScript Objects

Recently uploaded

JavaScript Objects