Length of Array.prototype - ES 5

Question

In type objects, a functionproperty lengthmeans the number of arguments expected by a type object function. For example, the field of an lengthobject function, the object Array, in the visualization below, matters 1.

In the above visualization, the field is lengthalso a member of the objecttype object Array.prototypewhose value 0.

MDN says:

Array.prototype.length reflects the number of elements in the array.

Following this definition below carsand bikesarray,

var cars = new Array("Saab", "Volvo", "BMW");
var bikes = ["Honda", "Yamaha"];

cars.__proto__.lengthand bikes.__proto__.lengthstill 0.

Multiple array objects ( cars, bikes) cannot use the same property value lengthbecause the property lengthis in Array.prototype.

1)

According to MDN , is this the correct definition?

2)

If not, what does the field mean lengthin Array.prototype?

Answer 1

MDN says:

Array.prototype.length reflects the number of elements in the array.

Is this the correct definition?

Varieties, yes. There are three different properties .lengthassociated with arrays:

• Array.length. As you said, this is an instance property ("native") that has all the functions and has nothing to do with arrays.
• arr.length, arr - (, arr = ['ex', 'ample']). , /, , .
• Array.prototype.length # 2, Array.prototype - , .length == 0.

MDN , . , cars, bikes Array.prototype .length ( , , ).

. Array.prototype.length? , , , Array.prototype. , , , Array.prototype , , .length ( ) , Array.prototype - , .

Answer 2

var cars = new Array("Saab", "Volvo", "BMW"); 
var bikes = ["Honda", "Yamaha"]; 

cars.__proto__.length bikes.__proto__.length - 0.

, cars.length === 3 bikes.length === 2.

cars.__proto__.length - prototype Array. .

Array.prototype - . var cars = new Array() __proto__, Array.prototype. cars.__proto__ === Array.prototype.

length - Array, . , .

var a = [];
a[10] = 'foo';
a.length; // 11

Array.prototype .

cars.__proto__.length === 0