Detecting array types

Interview when asked how to detect an unknown variable is not an array type, shame ah, the ancestors of the face are lost, this will not, go home moreing go!!!

var a = [];
Method One: Array.isarray ([])//true

typeof A here is not helpful, for the array type returned is an object, and for all but the function of all objects are so, heart tired, busy!

Method Two: a instanceof Array//true
But not as a reliable method of array detection.

Method Three: Detects the Class property of the object, and for an array the value of the property is always ' array ',

Object.prototype.toString () method, so the code for the IsArray () function can be Jiangzi written

var function (o) {     returntypeof o = = = ' Object     ' && = = = ' [Object Array] ';}

Detecting array types