JavaScript Arrays 101
Hey Everyone,
In this blog, we will learn about JavaScript arrays.
When writing programs, we often need to store multiple values.
For example:
A list of fruits
Marks of students
A list of tasks
A list of movies
Storing each value in a separate variable quickly becomes messy.
Let's see why.
The Problem Without Arrays
Imagine you want to store 5 games.
let game1 = "GTA 6";
let game2 = "FIFA 25";
let game3 = "F1 25";
let game4 = "God of war";
let game5 = "Call of duty";
Now imagine storing 50 games like this.
It becomes very difficult to manage.
This is where arrays help.
What is an Array?
An array is a collection of values stored in order.
Think of it like a list.
Example:
let students = ["abhi", "sameer", "deku", "eren", "dhoni"];
Now all values are stored in one variable called students.
How to Create an Array
Arrays are created using square brackets [].
Example:
let numbers = [10, 20, 30, 40];
Another example:
let colors = ["Red", "Green", "Blue"];
Arrays can store different types of values.
let data = ["Rahul", 25, true];
But usually arrays contain similar types of values.
Array Index
Every element in an array has a position called an index.
Important rule:
Array indexing starts from 0.
Example:
let fruits = ["Apple", "Banana", "Mango"];
Visual representation:
Index: 0 1 2
Value: Apple Banana Mango
Accessing Array Elements
We access elements using index numbers.
Example:
let fruits = ["Apple", "Banana", "Mango"];
console.log(fruits[0]); // Apple
Updating Array Elements
You can also change values inside an array.
Example:
let fruits = ["Apple", "Banana", "Mango"];
console.log(fruits); // ["Apple", "Banana", "Mango"]
fruits[1] = "Orange";
console.log(fruits); // ["Apple", "Orange", "Mango"]
Array Length Property
Arrays have a special property called length.
It tells us how many elements are inside the array.
Example:
let fruits = ["Apple", "Banana", "Mango"];
console.log(fruits.length); // 3
This is very useful when working with loops.
Looping Over Arrays
Instead of printing each element manually, we can use a loop.
Example using for loop:
let fruits = ["Apple", "Banana", "Mango", "Orange"];
for (let i = 0; i < fruits.length; i++) {
console.log(fruits[i]);
}
Output
Apple
Banana
Mango
Orange
The loop goes through each element of the array.
Practice Assignment
Try this in your browser console.
Step 1: Create an Array
Create an array of your 5 favorite movies.
Example:
let movies = ["Inception", "Avengers", "Interstellar", "Batman", "Joker"];
Step 2: Print First Element
console.log(movies[0]);
Step 3: Print Last Element
console.log(movies[movies.length - 1]);
Step 4: Update One Value
movies[2] = "Spider-Man";
console.log(movies);
Step 5: Loop Through the Array
for (let i = 0; i < movies.length; i++) {
console.log(movies[i]);
}
And now, you know what arrays are.
If you have any doubt or want to connect, feel free to drop a comment — I’d be happy to help.
Thanks for reading, and see you in the next blog!
Peace ✌️ and Happy Learning!
