Summary  
This chapter introduces arrays as ordered sequences of variables stored in a single structure and demonstrates accessing individual elements using zero-based indexing.

General domain of usage  
Organizing and managing collections of related data (e.g., storing lists of student names).

An **array** is simply an ordered collection of variables. 

Definition

## Defining an Array
The general syntax of defining an array is:

```js
let arrayName = [ element1, element2, … ];
```

We can declare an empty array as well:
```
let arrayName = [];
```

Arrays are useful when we need to store multiple values in a single variable instead of creating separate variables for each value. 

This makes data easier to organize and manipulate. For example, we can store the names of the class students in an array:

We can output all the elements of an array by simply using it's name in a console.log statement:



let students = [ "Emma", "Alex", "Chris" ];
console.log(students);

let emptyArray = [];
console.log(emptyArray);

## Indexing
We can access an element at a specific position in the array by **indexing**. 

The syntax for **indexing** is:
```js
arrayName[index]
```

Here `arrayName` is the name of the array, and `index` refers to the position of the element in the array. 

**The index values start from** `0`, which means the first element always has an index `0`.

let students = [ "Emma", "Alex", "Chris" ];
console.log(students[0]); // Output: Emma
console.log(students[1]); // Output: Alex
console.log(students[2]); // Output: Chris

Using an invalid index returns `undefined`:

let students = [ "Emma", "Alex", "Chris" ];
console.log(students[-1]); // Output: undefined
console.log(students[4]); // Output: undefined

Which of the following is the correct way to declare an array?

What will be the output of the following code?

Dive into the world of the most popular language for front-end development – JavaScript. JavaScript is a language built into almost every browser and can be used for a wide variety of tasks. Learn the basic functionality and prepare yourself for the challenges and more advanced programming techniques.

An introduction to JavaScript, covering the basic syntax of the language along with key terms and concepts that form the foundation for learning advanced features. The section includes hands-on tasks designed to help practice these concepts and make the content easy to remember without effort.

What Are Arrays?

Defining an Array

Indexing

1. What is an array in JavaScript?

2. Which of the following is the correct way to declare an array?

3. What does the following code output?

4. What will be the output of the following code?