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JavaScript/Typescript - 16 Topics

DEEP DIVE INTO

JavaScript/Typescript

Topic:object methods and properties

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In JavaScript, objects are a fundamental data structure that allows you to store and organize data. Objects can have both properties and methods, and they play a crucial role in object-oriented programming (OOP) in JavaScript. Here's an in-depth explanation of object properties and methods:

Object Properties:

1. Definition:

Properties are the characteristics or attributes of an object. They are essentially variables that are associated with an object.

2. Declaration and Initialization:

Properties are declared and initialized when an object is created using object literals or constructor functions.

javascript// Object literal
const person = {
  name: "John",
  age: 30,
};

// Constructor function
function Car(make, model) {
  this.make = make;
  this.model = model;
}
const myCar = new Car("Toyota", "Camry");

3. Accessing Properties:

You can access object properties using "dot notation" or "bracket notation".

javascriptconsole.log(person.name); // Using dot notation
console.log(person["age"]); // Using bracket notation

4. Data Types:

Properties can hold values of any data type, including primitive data types (e.g., strings, numbers) and complex data types (e.g., other objects or arrays).

javascriptconst user = {
  name: "Alice",
  age: 25,
  address: {
    city: "New York",
    zipCode: "10001",
  },
  hobbies: ["reading", "swimming"],
};

Object Methods:

1. Definition:

Methods are functions that are associated with an object. They define the behavior or actions that can be performed on an object.

2. Declaration and Initialization:

Methods are defined as functions within an object literal, constructor function, or class.

javascript// Object literal
const person = {
  name: "John",
  greet: function() {
    console.log(`Hello, my name is ${this.name}.`);
  },
};

// Constructor function
function Calculator() {
  this.add = function(a, b) {
    return a + b;
  };
}
const calculator = new Calculator();

3. Accessing Methods:

You can call object methods using "dot notation" this keyword refers to the object itself within the method.

javascriptperson.greet(); // Call the 'greet' method
const result = calculator.add(5, 3); // Call the 'add' method

4. Behavior:

Methods allow objects to encapsulate behavior, making them self-contained and reusable. They often perform operations on the object's properties or interact with the external environment.

javascriptconst circle = {
  radius: 5,
  area: function() {
    return Math.PI * this.radius ** 2;
  },
};

Object properties and methods are fundamental for organizing and manipulating data in JavaScript. They help create a structured and self-contained code, allowing for more modular and maintainable applications.

Objects can encapsulate both data (properties) and behavior (methods), making them a versatile and powerful programming construct in JavaScript.

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