如何找出一个对象是否是javascript中的数组？

Question

While going through javascript tutorial on 'W3Schools', I found this bit of code explaining how to to find out if an object is an Array.

function isArray(myArray) {
    return myArray.constructor.toString().indexOf("Array") > -1;
}

I am not understanding how does that particular line executes.

Link to W3School's page in question

Answer 1

Even if this question has accepted answer about a right way of using Array.isArray()

Question was about executing particular code from W3Schools, so for educational reasons there is what is happening in code example.

myArray.constructor is reference to object constructor. More at Link

With that in mind, we can proceed to:

myArray.constructor.toString()

Will result into

function Array() { [native code] }

Function indexOf will return position of string sequence in other string sequence. If string we are looking for is found it will return int position. If not indexOf will return -1.

Function could be described as If position of "Array" in stringified contructor of object is greater then -1, object is array.

Hope this helps.