Javascript 如何在javascript中访问对象原型？
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How to access object prototype in javascript?
提问by BreakPhreak
In all the articles it is written that JavaScript is a prototype-based language, meaning that every object has a prototype (or, more precisely, prototype chain).
在所有文章中，JavaScript 是一种基于原型的语言，这意味着每个对象都有一个原型（或者更准确地说，原型链）。
So far, I've tried the following code snippet:
到目前为止，我已经尝试了以下代码片段：
var F = function();
F.prototype.member1 = 1;
var object1 = new F();
console.log(object1.member1); // prints 1
How can I access the prototype object of object1? Is there a browser-neutral way to do that (I mean, not relying on __proto__property? Seen thislink, but maybe there are new developments since 2010) If I can't, could you share please the rationale behind the hood?
如何访问 的原型对象object1？有没有一种浏览器中立的方式来做到这一点（我的意思是，不依赖__proto__财产？看到这个链接，但也许自 2010 年以来有新的发展）如果我不能，你能分享一下引擎盖背后的基本原理吗？
回答by Andrew D.
var f = function();
var instance = new f();
If you know name of instanceclass function, you can simply access prototype as:
如果您知道instance类函数的名称，您可以简单地访问原型为：
var prototype = f.prototype;
prototype.someMember = someValue;
If you don't:
如果你没有：
1)
1)
var prototype = Object.getPrototypeOf(instance);
prototype.someMember = someValue;
2)or
2)或
var prototype = instance.__proto__;
prototype.someMember = someValue;
3)or
3)或
var prototype = instance.constructor.prototype; // works only if constructor is properly assigned and not modified
prototype.someMember = someValue;
For compatibility you can place into your code the following snippet (and use always Object.getPrototypeOf(instance)to return prototype):
为了兼容性，您可以将以下代码段放入您的代码中（并使用 alwaysObject.getPrototypeOf(instance)返回原型）：
if(!Object.getPrototypeOf) {
if(({}).__proto__ === Object.prototype && ([]).__proto__ === Array.prototype) {
Object.getPrototypeOf = function getPrototypeOf(object) {
return object.__proto__;
};
} else {
Object.getPrototypeOf = function getPrototypeOf(object) {
// May break if the constructor has been changed or removed
return object.constructor ? object.constructor.prototype : void 0;
};
}
}
UPDATE:
更新：
According to ECMA-262 6th Edition (June 2015) __proto__property is standardized as additional feature for Web browsers. All latest editions of top browsers supports it now. Read more about __proto__:
根据 ECMA-262 第 6 版（2015 年 6 月），__proto__属性被标准化为 Web 浏览器的附加功能。现在所有最新版本的顶级浏览器都支持它。阅读更多关于__proto__：
EDMA-262 6th Edition (June 2015):
B.2.2.1 Object.prototype.__proto__
EDMA-262 第 6 版（2015 年 6 月）：
B.2.2.1 Object.prototype.__proto__
回答by HelloWorld
It looks like
看起来像
Object.getPrototypeOf(passedObject);
will work for this, and is compatible with modern browsers.
将为此工作，并与现代浏览器兼容。
Here are the compatibility tables on MDN
回答by HelloWorld
var F = function(){};
var object1 = new F();
alert(object1.constructor === F);
alert(object1.constructor.prototype === F.prototype);
回答by r3mark
var F = function();
F.prototype.member1 = 1;
F.prototype.getClass = F;
var object1 = new F();
object1.member1 = 2;
console.log(object1.getClass.prototype.member1); // prints 1
console.log(object1.member1); // prints 2
回答by Kado
var F = function();
F.prototype.member1 = 1;
var intance = new F();
console.log(instance['member1']);
