Non-static private variables in javascript

Question

I'm setting up my javascript objects like the following

Object1 = function() {
  var privateMember = "private value"

  return {
    publicMember: "public value"
    setPrivateMember: function(value) {
       privateMember = value;
    }
  }
}();

Now if I use prototypal inheritance to create new objects

Object2.prototype = Object1

And then set the private member

Object2.setPrivateMember("new value");

Then the value of private member in Object 1 changes too, so it behaves more like a static variable. Is there a way I can get private variables to not be static?

PS - I'm a self-taught programmer so my use of terminology might be a bit sketchy. Let me know if it needs clarifying

Should be using `Object2.prototype = Object1()`, or is that just a typo in the pasted code? — MooGoo, Sep 14 '10 at 14:35
possible duplicate of [Private variables in inherited prototypes](http://stackoverflow.com/questions/3617139/private-variables-in-inherited-prototypes) — TM., Sep 14 '10 at 14:47

score 3 · Accepted Answer · edited May 23 '17 at 11:48

3

Righto, knew I awnsered something like this before:
Private variables in inherited prototypes

;oP

edited May 23 '17 at 11:48

Community

1
1

answered Sep 14 '10 at 14:33

BGerrissen

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I knew it had to have been asked before, but just couldn't find the right phrase to search for. Cheers for the answer – wheresrhys Sep 14 '10 at 14:40

score 2 · Answer 2 · answered Sep 14 '10 at 14:26

2

You're creating a global variable. Put var before it.

var privateMember = "private value";

answered Sep 14 '10 at 14:26

Kyle Jones

536
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1

This was a typo in my question. Problem still happens even when I use var – wheresrhys Sep 14 '10 at 14:29

Sachin Shanbhag · Answer 3 · 2010-09-14T14:42:07.387

2

Edited my answer, can you check if this works?

Try this -

Object1 = function() {  
  var privateMember = "private value"; 

  var returnVal =  {  
                publicMember: "public value",  
                setPrivateMember: function(value) {  
                privateMember = value;  
                }

           }; 
  return returnVal; 
}();

edited Sep 14 '10 at 14:42

answered Sep 14 '10 at 14:27

Sachin Shanbhag

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Non-static private variables in javascript

3 Answers3