How to access object prototype in javascript?

Question

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).

So far, I've tried the following code snippet:

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 this link, but maybe there are new developments since 2010) If I can't, could you share please the rationale behind the hood?

Answer 1

var f = function(); var instance = new f(); 

If you know name of instance class function, you can simply access prototype as:

var prototype = f.prototype; prototype.someMember = someValue; 

If you don't:

1)

var prototype = Object.getPrototypeOf(instance); prototype.someMember = someValue; 

2) or

var prototype = instance.__proto__; prototype.someMember = someValue; 

3) or

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):

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:

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__:

• MDN: Object.prototype.__proto__

• EDMA-262 6th Edition (June 2015): B.2.2.1 Object.prototype.__proto__