Javascript Objects

Object Literals:

Object literals is a one-liner convenient way to create object which we can accomplish using a single line.

                                      
                                        // Object literal
let person = {
    firstName: "John",
    lastName: "Doe",
    age: 30,
    greet: function() {
        console.log("Hello, " + this.firstName + "!");
    }
};

// Accessing properties
console.log(person.firstName); // Output: "John"

// Accessing methods
person.greet(); // Output: "Hello, John!"

In this example, person is an object with properties (firstName, lastName, age) and a method (greet).


Object Constructors:

Object constructors allows instantiation of objects that have many similar structures.

Constructors are functions that are used just like any of the other normal functions with the new keyword.

                                      
                                        // Object constructor
function Person(firstName, lastName, age) {
    this.firstName = firstName;
    this.lastName = lastName;
    this.age = age;
    this.greet = function() {
        console.log("Hello, " + this.firstName + "!");
    };
}

// Creating objects using the constructor
let person1 = new Person("John", "Doe", 30);
let person2 = new Person("Jane", "Doe", 25);

// Accessing properties
console.log(person1.firstName); // Output: "John"
console.log(person2.age); // Output: 25

// Accessing methods
person1.greet(); // Output: "Hello, John!"
person2.greet(); // Output: "Hello, Jane!"

In this example, Person is an object constructor, and person1 and person2 are instances created using this constructor.


Accessing Properties and Methods:

You can access properties and methods of objects using dot notation.

                                  
                                    let car = {
                                        brand: "Toyota",
                                        model: "Camry",
                                        start: function() {
                                            console.log("Engine started!");
                                        }
                                    };
                                    
                                    // Accessing properties
                                    console.log(car.brand); // Output: "Toyota"
                                    
                                    // Accessing methods
                                    car.start(); // Output: "Engine started!"

Adding and Modifying Properties:

You can add or modify properties of objects dynamically.

                                  
                                    let person = {
                                        firstName: "John",
                                        lastName: "Doe"
                                    };
                                    
                                    // Adding a new property
                                    person.age = 30;
                                    
                                    // Modifying an existing property
                                    person.lastName = "Smith";
                                    
                                    console.log(person); // Output: { firstName: "John", lastName: "Smith", age: 30 }