How to Create Array in JavaScript: Syntax and Examples

In JavaScript, you can create an array using the Array constructor or by using square brackets []. The square bracket syntax is the most common and simple way to create an array with elements inside.

Syntax

You can create an array in JavaScript in two main ways:

• Using square brackets: This is the simplest way to create an array with elements.
• Using the Array constructor: This creates an array object, optionally with a specified length or elements.

javascript

const array1 = ['element1', 'element2', 'element3'];
const array2 = new Array('element1', 'element2', 'element3');
const emptyArray = [];

Example

This example shows how to create arrays using both methods and how to access elements.

javascript

const fruits = ['apple', 'banana', 'cherry'];
console.log(fruits[0]); // apple

const numbers = new Array(1, 2, 3);
console.log(numbers[2]); // 3

const empty = [];
console.log(empty.length); // 0

Output

apple
3
0

Common Pitfalls

One common mistake is using the Array constructor with a single number, which creates an empty array of that length instead of an array with that number as an element.

For example, new Array(3) creates an empty array with length 3, not an array containing the number 3.

javascript

const wrong = new Array(3);
console.log(wrong.length); // 3
console.log(wrong); // [ <3 empty items> ]

const right = [3];
console.log(right.length); // 1
console.log(right); // [3]

Output

3
[ <3 empty items> ]
1
[3]

Quick Reference

Method	Description	Example
Square Brackets	Create array with elements	const arr = [1, 2, 3];
Array Constructor	Create array with elements or length	const arr = new Array(1, 2, 3);
Array Constructor with single number	Creates empty array of that length	const arr = new Array(5);

Key Takeaways

Use square brackets [] to create arrays easily with elements.

The Array constructor can create arrays but behaves differently with a single number.

Access array elements by their index starting at 0.

Empty arrays have a length of 0 and contain no elements.

Avoid using new Array(number) unless you want an empty array of that length.