Question

So there has been much discussion on the topic of accessing private members inside of prototype methods. The thought occurred to me that the following should work:

function Test(){
    var private = "Private";
    this.instance = function(){
        return private;
    };

    Test.prototype.getPrivate = function(){
        return private;
    };
}
var test1 = new Test();
var test2 = new Test();
console.log(test1.instance === test2.instance);  // false
console.log(test1.getPrivate === test2.getPrivate);  // true

Turns out it does, in fact, work. I’m concerned, however, that there might be a drawback to doing this.

So my question is: Is there a drawback?

Answer 1

This doesn’t work the way you probably expect, as test1‘s getPrivate() gets test2‘s private.

function Test(value){  
    var private = value;  
    this.instance = function(){ return private; };

    Test.prototype.getPrivate = function(){  
        return private;  
    };  
}  
var test1 = new Test("test1");  
var test2 = new Test("test2");
console.log(test1.getPrivate()); // test2
console.log(test2.getPrivate()); // test2

so it really doesn’t matter if it is inefficient as it doesn’t work.