javascript - __proto__ VS。 JavaScript 中的原型(prototype)

Question

This figure again shows that every object has a prototype. Constructor function Foo also has its own __proto__ which is Function.prototype, and which in turn also references via its __proto__ property again to the Object.prototype. Thus, repeat, Foo.prototype is just an explicit property of Foo which refers to the prototype of b and c objects.

var b = new Foo(20);
var c = new Foo(30);

__proto__和prototype有什么区别？

图取自dmitrysoshnikov.com .

注意:现在有 a 2nd edition (2017)到上面2010年的文章。

Answer 1

__proto__是在查找链中用于解析方法等的实际对象。prototype是用于构建 __proto__ 的对象当您使用 new 创建对象时:

( new Foo ).__proto__ === Foo.prototype
( new Foo ).prototype === undefined