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Object in JavaScript-tutorial

In JavaScript, an object is like a real-world entity that has properties (state) and behaviors (methods).
Objects help store and organize data in a key-value pair format, making your code cleaner and more flexible.

Creating Objects in JavaScript

There are three main ways to create an object

Using Object Literal Notation

Using the new keyword (direct instance)

Using Object Constructor

Using Object Literal Notation

This is the simplest and most common way.
You directly define the object inside curly braces {}.

Syntax:

var person = {
   firstName: "John",
   lastName: "Doe",
   age: 30
};

Example:

<!DOCTYPE html>
<html>

<body>
    <script>
        var emp = { id: 102, name: "Shyam Kumar", salary: 40000 };
        document.write(emp.id + " " + emp.name + " " + emp.salary);
    </script>
</body>

</html>

Output

Using new keyword (direct instance)

You can also create an object by instantiating object directly.

Syntax:

var objectName = new Object();

Example:

<!DOCTYPE html>
<html>

<body>
    <script>
        var emp = new Object();
        emp.id = 101;
        emp.name = "Ravi Malik";
        emp.salary = 50000;
        document.write(emp.id + " " + emp.name + " " + emp.salary);
    </script>
</body>

</html>

Output

Using Object Constructor

This method uses a constructor function to create multiple similar objects.

Syntax:

function Person(firstName, lastName, age) {
   this.firstName = firstName;
   this.lastName = lastName;
   this.age = age;
}
var p = new Person("John", "Doe", 30);

Example:

<!DOCTYPE html>
<html>

<body>
    <script>
        function emp(id, name, salary) {
            this.id = id;
            this.name = name;
            this.salary = salary;
        }
        var e = new emp(103, "Vimal Jaiswal", 30000);
        document.write(e.id + " " + e.name + " " + e.salary);
    </script>
</body>

</html>

Output

Objects are one of the most powerful features in JavaScript, used for modeling real-world data and building complex applications easily.