javascript Objects (part one)

Hi, this is my 8^th js tutorial which describes about the objects in JavaScript. Objects are very serious topic and we must have clear idea about objects in js for advance developments. After this object tutorial we will move on to an existing example.

So let’s move on…👉

If we consider object as a data type of js we can came to another judgment, it has five datatypes. Which means three primitive data types (numbers, string, Boolean), null and undefined data types.

An object is a list of primitive data types. We can initialize values to object as arrays or we can leave them empty. If the value is null or undefined, it will create and return an empty object, otherwise, it will return an object of a Type that corresponds to the given value. If the value is an object already, it will return the value. It is the simplest way to explain object.

OK let’s move to create an object.
This is a simple object …

var my_object = {firstName:”Chamini”, secondName:”prashakthi”};

Think as object is a list that contain item. So, according to the above example it is stored as name value pair. The property names are first_Name and second_Name and the values are chamini and prashakthi.

We can use strings or numbers as property names.

Like,

var marks={50:”bad”,75:”good”,100:”very good”};

Also we can create a js object using new operator.

var object1= new Object();

var object2= new Array(“dog”, ”cat”, ”cow”, ”tiger” );

If we create an empty object we can assign a value to that empty object in this way.

objetName.objectProperty = propertValue ;

Object methods

Objects do something using object methods. You know that all the previous tutorials we use document.write syntax. So here the document is an object and write() is a method in the js.

Object constructor

This is really important point to understand. So I will explain it in the simplest way. If you have ever learn any of object oriented language you may heard about constructors.

If not see below explanation.

Constructor is a function. The usage of a constructor is, it is use to create and initialize an object. Js provide object()function to create an object. Also we can assign or initialize a variable to an object using return value of the object() constructor.

Check the first demonstration.