JS Array IsArray - thelastmile/FreeCodeCamp GitHub Wiki

JavaScript Array.isArray

The Array.isArray() method returns true if an object is an array, false if it is not.

Syntax

Array.isArray(obj)

Parameters

obj The object to be checked.

MDN link | MSDN link

Examples

// all following calls return true
Array.isArray([]);
Array.isArray([1]);
Array.isArray(new Array());
// Little known fact: Array.prototype itself is an array:
Array.isArray(Array.prototype); 

// all following calls return false
Array.isArray();
Array.isArray({});
Array.isArray(null);
Array.isArray(undefined);
Array.isArray(17);
Array.isArray('Array');
Array.isArray(true);
Array.isArray(false);
Array.isArray({ __proto__: Array.prototype });