When writing programs, we often need to store multiple values together.
For example:

• A list of fruits

• A list of marks

• A list of tasks

• A list of movies

Instead of creating many separate variables, JavaScript gives us arrays.

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1. What Are Arrays?

An array is a collection of values stored in order.

Think of an array like a list.

Real-Life Example

Imagine a list of fruits:

Apple
Banana
Mango
Orange

Instead of writing separate variables:

let fruit1 = "Apple";
let fruit2 = "Banana";
let fruit3 = "Mango";

We can store them in one array.

let fruits = ["Apple", "Banana", "Mango"];

Now all values are stored together in one variable called fruits.

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2. How to Create an Array

Arrays are created using square brackets [].

Example

let fruits = ["Apple", "Banana", "Mango"];

Another example:

let numbers = [10, 20, 30, 40];

You can store different types of values too:

let mixed = ["Pankaj", 25, true];

But usually arrays store similar types of data.

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3. Accessing Elements Using Index

Each item in an array has a position number called an index.

Important rule:

Array index starts from 0

Example Array

let fruits = ["Apple", "Banana", "Mango"];

Index Visualization

Index:   0        1        2
      
Array:  Apple   Banana   Mango

To access elements:

console.log(fruits[0]);

Output

Apple

Another example:

console.log(fruits[1]);

Output

Banana

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4. Updating Elements

We can change values inside an array using the index.

Example

let fruits = ["Apple", "Banana", "Mango"];

fruits[1] = "Orange";

console.log(fruits);

Output

["Apple", "Orange", "Mango"]

Here we changed Banana → Orange.

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5. Array Length Property

The length property tells us how many elements are in the array.

Example

let fruits = ["Apple", "Banana", "Mango"];

console.log(fruits.length);

Output

3

This is very useful when working with loops.

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6. Looping Through an Array

Often we want to process every element in the array.

We can do this using a loop.

Example

let fruits = ["Apple", "Banana", "Mango"];

for (let i = 0; i < fruits.length; i++) {
  console.log(fruits[i]);
}

Output

Apple
Banana
Mango

Explanation:

• i starts from 0

• Loop runs until fruits.length

• Each iteration prints one element

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Visual Representation of Array

Index:    0        1        2        3
       
Array:   Apple   Banana   Mango   Orange

Accessing elements:

fruits[0] → Apple
fruits[1] → Banana
fruits[2] → Mango
fruits[3] → Orange

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Memory Style Diagram

Each block stores one value in order.

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Arrays are used everywhere in JavaScript, such as:

• storing user data

• product lists

• scores

• API responses