私有成员对象包含函数

Question

In javascript, I have an object containing a function and want to add to it a private member. How can I do that?

function function1 () {
    var function2 = function () {
        console.log("This is an actual function.");
    }

    function2.publicMember = 5;
    function2.privateMember = 7; 

    return function2;
}

I want privatMember to be inaccessible to the user of function1. I found this question but I can't quite translate it to my situation because my object is a function:

How to add private variable to this Javascript object literal snippet?

thanks!

Answer 1

Wrap it into one more function to create new scope (ie using iife ):

function function1 () {
     var function2 = (function(){
       var privateMember = 7; 
       return function () {
          privateMember ++; // do something with really private member
          console.log("This is an actual function.");
       }
    })();

    function2.publicMember = 5;

    return function2;
}

Answer 2

Declare the vars inside the function that needs access to them:

function function1 () {
    var publicMember = 5;
    var function2 = function () {
        var privateMember = 7;
        console.log("This is an actual function.");
    }

    return function2;
}

So function2 can see the vars inside its own closure (privateMember) and any parent scope.