JavaScript Data Types

In JavaScript, data types define the kind of values a variable can hold. Understanding data types is crucial for writing accurate and efficient code. Let's explore the fundamental data types available in JavaScript.

Primitive Data Types

Primitive data types represent basic values and are immutable. They are the building blocks of more complex data structures.

• **Number:** Represents numerical values, including integers and decimals.

let age = 25;
let price = 19.99;

• **String:** Represents textual data, enclosed within single or double quotes.

let name = "John Doe";
let message = 'Hello, world!';

• **Boolean:** Represents truth values, either `true` or `false`.

let isLoggedIn = true;
let isCompleted = false;

• **Null:** Represents the intentional absence of a value.

let emptyValue = null;

• **Undefined:** Represents a variable that has been declared but not assigned a value.

let myVariable; // myVariable is undefined

Object Data Type

Object data type allows you to create complex data structures that store collections of key-value pairs. Objects are mutable, meaning their properties can be modified after creation.

let person = {
  name: "Jane Doe",
  age: 30,
  occupation: "Software Engineer"
};

Object Properties

Properties are key-value pairs within an object. They hold data associated with the object.

person.name; // Accessing the 'name' property
person.age = 31; // Modifying the 'age' property

Object Methods

Methods are functions associated with an object. They define actions or behaviors that the object can perform.

let myObject = {
  greet: function() {
    console.log("Hello from the object!");
  }
};
myObject.greet(); // Calling the 'greet' method

Summary

• JavaScript has primitive and object data types.
• Primitive data types include Number, String, Boolean, Null, and Undefined.
• Object data type enables complex data structures with properties and methods.
• Understanding data types is crucial for writing accurate and efficient JavaScript code.