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Javascript Objects

Javascript

JavaScript objects are complex data structures used to store collections of key-value pairs. They are fundamental to JavaScript programming and provide a way to represent real-world entities and their properties. Here's an overview of key concepts related to JavaScript objects:

  1. Object Declaration:

    Objects are declared using curly braces {}.

    javascript
    let obj = {}; // Empty object
let person = {
    name: "John",
    age: 30,
    city: "New York"
}; // Object with properties

  2. Properties:

    Properties in an object consist of key-value pairs. The key is a string (or a Symbol), and the value can be of any data type.

    javascript
    let person = {
    name: "John",
    age: 30,
    city: "New York"
};
console.log(person.name); // Output: John
console.log(person.age); // Output: 30

  3. Accessing Properties:

    Object properties can be accessed using dot notation (objectName.propertyName) or bracket notation (objectName['propertyName']).

    javascript
    let person = {
    name: "John",
    age: 30,
    city: "New York"
};
console.log(person.name); // Dot notation
console.log(person['age']); // Bracket notation

  4. Adding and Modifying Properties:

    Object properties can be added or modified dynamically.

    javascript
    let person = {
    name: "John",
    age: 30,
    city: "New York"
};
person.gender = "Male"; // Adding a new property
person.age = 35; // Modifying an existing property

  5. Deleting Properties:

    Properties can be deleted from an object using the delete keyword.

    javascript
    let person = {
    name: "John",
    age: 30,
    city: "New York"
};
delete person.age; // Deleting a property

  6. Object Methods:

    Objects can also contain methods, which are functions associated with the object.

    javascript
    let person = {
    name: "John",
    age: 30,
    city: "New York",
    greet: function() {
        console.log(`Hello, my name is ${this.name}`);
    }
};
person.greet(); // Output: Hello, my name is John

  7. Object Iteration:

    Objects can be iterated over using loops like for...in loop or Object.keys, Object.values, Object.entries methods.

    javascript
    let person = {
    name: "John",
    age: 30,
    city: "New York"
};

// Using for...in loop
for (let key in person) {
    console.log(`${key}: ${person[key]}`);
}

// Using Object.keys
Object.keys(person).forEach(function(key) {
    console.log(`${key}: ${person[key]}`);
});

JavaScript objects are versatile and widely used in web development for organizing and manipulating data. They provide a flexible way to represent complex data structures and are a key feature of the language.

Thanks for learning