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Creating objects in JavaScript (4 Different Ways)

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JavaScript is a flexible object-oriented language when it comes to syntax. In this article, we will see the different ways to instantiate objects in JavaScript. Before we proceed it is important to note that JavaScript is an object-based language based on prototypes, rather than being class-based. Because of this different basis, it can be less apparent how JavaScript allows you to create hierarchies of objects and to have an inheritance of properties and their values.

These are the following 4 ways:

Creating object with a constructor

One of the easiest ways to instantiate an object is in JavaScript. Constructor is nothing but a function and with the help of a new keyword, the constructor function allows to creation of multiple objects of the same flavor as shown below: 

Example: This example shows the implementation of the above-explained approach.

javascript




// Simple function
function vehicle(name,maker,engine){
    this.name = name;
    this.maker = maker;
    this.engine = engine;
}
// New keyword to create an object
let car  = new vehicle('GT','BMW','1998cc');
// Property accessors
console.log(car.name);
console.log(car.maker);
console.log(car['engine']);


Output

GT
BMW
1998cc

Explanation: A class in OOPs have two major components, certain parameters and few member functions. In this method we declare a function similar to a class, there are three parameters, name, maker and engine ( the this keyword is used to differentiate the name,maker,engine of the class to the name,maker,engine of the arguments that are being supplied.). We then simple create an object obj of the vehicle, initialize it and call it’s method.  

Using object literals

Literals are smaller and simpler ways to define objects. We simply define the property and values inside curly braces as shown below.

Example: This example shows the implementation of the above-explained approach.

javascript




// Creating js objects with object literal
let car = {
    name : 'GT',
    maker : 'BMW',
    engine : '1998cc'
};
// Property accessor
console.log(car.name); //dot notation
console.log(car['maker']); //bracket notation


Output

GT
BMW

In the above code, we created a simple object named car with the help of object literal,having properties like name,maker,engine.Then we make use of the property accessor methods(Dot notation,Bracket notation) to console.log the values. Now let’s see how we can add more properties to an already defined object: 

javascript




let car = {
    name : 'GT',
    maker : 'BMW',
    engine : '1998cc'
};
// Adding property to the object
car.brakesType = 'All Disc';
console.log(car);


Output

{ name: 'GT', maker: 'BMW', engine: '1998cc', brakesType: 'All Disc' }

 Methods can also be part of the object while creation or can be added later like properties as shown below: 

javascript




// Adding methods to the car object
let car = {
    name : 'GT',
    maker : 'BMW',
    engine : '1998cc',
    start : function(){
        console.log('Starting the engine...');
    }
};
car.start();
// Adding method stop() later to the object
car.stop = function() {
    console.log('Applying Brake...'); 
}
car.stop();


Output

Starting the engine...
Applying Brake...

Explanation: In the above code start method was added to the car object and later called by the car.start() and also the stop method was added too after the object was already declared.  

Creating object with Object.create() method

The Object.create() method creates a new object, using an existing object as the prototype of the newly created object.

Example: This example shows the implementation of the above-explained approach.

javascript




const coder = {
    isStudying : false,
    printIntroduction : function(){
        console.log(`My name is ${this.name}. Am I studying?: ${this.isStudying}`);
    }
};
const me = Object.create(coder);
me.name = 'Mukul';
me.isStudying = true;
me.printIntroduction();


Output

My name is Mukul. Am I studying?: true

Using es6 classes

ES6 supports class concept like any other Statically typed or object oriented language. So, object can be created out of a class in javascript as well.

Example: This example shows the implementation of the above-explained approach.

javascript




// Using es6 classes
class Vehicle {
  constructor(name, maker, engine) {
    this.name = name;
    this.maker =  maker;
    this.engine = engine;
  }
}
 
let car1 = new Vehicle('GT', 'BMW', '1998cc');
 
console.log(car1.name);  //GT


Output

GT


Last Updated : 13 Dec, 2023
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