day-18

Objects in JavaScript: Properties, Methods, and JSON

Objects are an essential part of JavaScript and are used to represent and organize data in a structured way. In this guide, we'll explore how to create objects, work with their properties and methods, and understand JSON, which is closely related to JavaScript objects.

Creating Objects

Objects in JavaScript are created by enclosing key-value pairs within curly braces {}.

// Creating an empty object
const person = {};

// Creating an object with properties
const user = {
  firstName: 'John',
  lastName: 'Doe',
  age: 30,
};

// Creating an object with methods
const car = {
  brand: 'Toyota',
  model: 'Camry',
  start: function() {
    console.log('Engine started');
  },
  stop: function() {
    console.log('Engine stopped');
  },
};

Accessing Object Properties

You can access object properties using dot notation (.) or square brackets [].

const user = {
  firstName: 'John',
  lastName: 'Doe',
  age: 30,
};

console.log(user.firstName); // 'John'
console.log(user['lastName']); // 'Doe'

Modifying Object Properties

Object properties can be modified by assigning new values to them.

const user = {
  firstName: 'John',
  lastName: 'Doe',
};

user.firstName = 'Alice';

console.log(user.firstName); // 'Alice'

Adding New Properties

You can add new properties to an object at any time.

const user = {
  firstName: 'John',
  lastName: 'Doe',
};

user.age = 30;

console.log(user.age); // 30

Methods

In JavaScript, object properties can also hold functions, which are called methods.

const calculator = {
  add: function(a, b) {
    return a + b;
  },
  subtract: function(a, b) {
    return a - b;
  },
};

const sum = calculator.add(5, 3);
console.log(sum); // 8

Working with Objects in JavaScript - Day 18: Assignment

Submission Guidelines:

1. Read the assignment instructions in the index.js file and organize your code and files neatly in the javascript-tasks/day-18 folder.
2. Make sure to save it into your own repository. ALL tasks will be evaluated after the submission deadline in order to claim your certificate.