The correct way to check if a variable is an array is using 'arr instanceof Array' or the more recommended 'Array.isArray(arr)'. The typeof operator returns 'object' for arrays, not 'array', so typeof arr === 'array' would be false. There is no .type property on arrays, and isArray() is a static method on the Array constructor, not a method on array instances, so arr.isArray() would result in an error.