I am now on YouTube!

My channel

Checking if something is an array

Internally, there is no type called “array” in JavaScript. When used on an array, typeof returns "object" instead.

To check if something is an array, use Array.isArray() instead.

// `typeof` an array returns “object” because JS has no type called “array”.
typeof ['a', 'b', 'c']                     // ⇒ "object"

// The array is treated like this equivalent object.
typeof { 0: 'a', 1: 'b', 2: 'c' }          // ⇒ "object"

// Use `Array.isArray` instead of `typeof` to test if something is an array.
Array.isArray(['a', 'b', 'c'])             // ⇒ true
Array.isArray({ 0: 'a', 1: 'b', 2: 'c' })  // ⇒ false

There is more to learn

Get free previews of my upcoming course materials and other bonus content to help you work smarter. I share tips straight to your inbox once a week. You can read previous mails in the newsletter archive.

Cannot show form because cookie consent was not given.