JAVASCRIPT OBJECTS

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JavaScript Objects

A JavaScript object is an entity with state and behavior, represented by properties and methods. Examples include a car, pen, bike, chair, glass, keyboard, monitor, etc.

JavaScript is an object-oriented language where everything is treated as an object.

JavaScript is template-based, not class-based. Instead of creating classes to generate objects, we directly create objects.

Creating Objects in JavaScript


There are three ways to create objects.

1. Using an object literal.

2. By directly creating an instance of Object using the `new` keyword.

3. By using an object constructor with the `new` keyword.

JavaScript Object by object literal


The syntax for creating an object using an object literal is shown below:

Syntax 

let objectName = {
  propertyName1: value1,
  propertyName2: value2,
  propertyName3: value3,
};

As you can see, the property and value are separated by a colon (:).

Let’s look at a simple example of creating an object in JavaScript.

Example 

<Script>

let car = {
  color: 'red',
  model: 'Toyota',
  year: 2004
};

console.log(car.color); 
console.log(car.model); 
console.log(car.year); 

</Script>

Output :

Red 
 
Toyota

2004

By creating instance of Object


The syntax for creating an object directly is shown below:

Syntax 


let objectName = {
  property1: value1,
  property2: value2,
  property3: value3,
  ...
};

In this case, the `new` keyword is used to create the object.

Let’s look at an example of creating an object directly.

Example 

<Script>

let person = {
  name: 'Anya',
  age: 19,
  city: 'Chennai'
};

console.log(person.name); 
console.log(person.age); 
console.log(person.city);

</Script>

Output:

Anya

19

Chennai 

By using an Object constructor


Here, you need to create a function with arguments. Each argument value can be assigned to the current object using the `this` keyword.

The `this` keyword refers to the current object.

An example of creating an object using an object constructor is shown below.

Example 

<Script>

let person = new Object();
person.name = 'kakashi';
person.age = 23;
person.city = 'Chennai';

console.log(person.name); 
console.log(person.age); 
console.log(person.city); 

</Script>

Output:


Kakashi

23

Chennai 

Defining method in JavaScript Object


In JavaScript, you can define a method in an object, but before defining the method, you need to add a property with the same name as the method in the function.

Example 

<Script>

let person = {
  name: 'Anya',
  age: 19,
  city: 'Chennai',
  greet: function() {
    console.log('Hello, my name is ' + this.name);
  }
};

person.greet(); 

</Script>

Output: 

Hello, my name is Anya

JavaScript Object Methods


The different methods of Object are as follows:







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