Javascript and prototype of __proto__

proto (implicit prototype) and the prototype (prototype explicit)

　　What is?

Explicit prototype explicit prototype property:

Each function after you create will have a property named prototype, this property points to the prototype object function.

Implicit prototype implicit prototype link:

Any JavaScript object has a built-in attribute [[the prototype]], there is no standard way to access ES5 before the built-in properties,

However, most browsers support access by __proto__. With the built-in ES5 attribute criteria for the Get method of Object.getPrototypeOf ().
　　Object.prototype This object is an exception, its value is null __proto__

Relations between the two:

Implicit prototype point to create the object constructor (constructor) of the prototype

　　effect?

Explicit action prototype: Prototype for sharing on inheritance and attribute.

Implicit action prototype: Prototype chain configuration, for achieving the same prototype-based inheritance. For example, when we visited the x property of the object obj,

　　　If you can not find in obj, then it will in turn look down __proto__.

Example:

A constructor declaration, a prototype of the object A and a method of adding an attribute,

A function to create an object with a:

1 A.prototype.name = "Jack";
2 A.prototype.say = function () {
3     console.log("hello");
4 }
6 function A() {
7     8 }
9 var a = new A( );

Let's look at the output wave of the console. . .

First, the object of a __proto __ (implicit prototype) point A the prototype (prototype object)

And a .__ proto __.__ proto__ and equivalent to the following long list of things that, in fact, is equivalent to the prototype object --Object.prototype ancestor of all objects

In the definition of the prototype chain, i.e. Object.prototype prototype chain end, there is no upward.

A prototype of the constructor, which is a target of the place pointed __proto__

* Proto A constructor of what they point to?

Implicit prototype point constructor of the object constructor function prototype (A .__ proto__ === A.constructor.prototype).

Because the function is a special object , " Function.prototype"that is, all function prototypes, is usually considered a Function function can be manufactured by the new.

换句话说，Function.prototype上面承载了用于继承给所有函数的那些属性，例如：call、bind、apply等。

部分内容参考自：https://www.zhihu.com/question/34183746/answer/59043879