JS Arrays

JavaScript Arrays: A Beginner's Guide

A JavaScript Array is a special type of variable that can hold more than one value at a time. If you have a list of items (like a list of car names or a list of numbers), storing the items in single variables could look like this:

let car1 = "Saab";
let car2 = "Volvo";
let car3 = "BMW";

This is cumbersome and not scalable. Arrays solve this problem by allowing you to store multiple values in a single reference.

1. What is an Array?

An array is an ordered collection of values. Each value is called an element, and each element has a numeric position in the array, known as its index.

• Ordered Collection: The elements in an array are stored in a specific sequence.
• Zero-Indexed: The first element is at index 0, the second is at index 1, and so on.

2. Creating an Array

The simplest way to create an array is by using an array literal.

Array Literal Syntax (Recommended)

The array literal syntax uses square brackets [] to wrap a comma-separated list of elements.

const cars = ["Saab", "Volvo", "BMW"];
console.log(cars);

3. Accessing Array Elements

You can access an individual element in an array by referring to its index number inside square brackets.

const cars = ["Saab", "Volvo", "BMW"];

// Access the first element (index 0)
let firstCar = cars[0];
console.log(firstCar); // Outputs: Saab

4. Changing an Array Element

You can change the value of an element by accessing it via its index and assigning a new value.

const cars = ["Saab", "Volvo", "BMW"];

// Change the first element
cars[0] = "Opel";
console.log(cars); // Outputs: ["Opel", "Volvo", "BMW"]

5. The length Property

The length property of an array returns the number of elements it contains.

const fruits = ["Banana", "Orange", "Apple", "Mango"];
let length = fruits.length;

console.log(length); // Outputs: 4