Array.isArray()

The Array.isArray() static method determines whether the passed value is an Array.

Array.isArray() checks if the passed value is an Array. It performs a branded check, similar to the in operator, for a private field initialized by the Array() constructor.

It is a more robust alternative to instanceof Array because it avoids false positives and false negatives:

Array.isArray() rejects values that aren’t actual Array instances, even if they have Array.prototype in their prototype chain — instanceof Array would accept these as it does check the prototype chain. Array.isArray() accepts Array objects constructed in another realm — instanceof Array returns false for these because the identity of the Array constructor is different across realms.

Syntax example: Array.isArray(value)