Javascript私有方法和私有类变量

Question

I'm not a professional Javascript dev, so my experience is limited to personal projects using tutorials online as well as trial and error. I've just recently had the need to create an object that has its own methods and member variables etc. I've been reading Doug Crockford notes and others stuff but I'm struggling to understand how it all fits together.

Consider the following code:

var CLASS_VAR = "some_val";

function MyClass(opts) {
    this.options = opts;
    this.myContainer = null;
}

MyClass.prototype.doIt = function() {

    var privateMethod = function(options) {
        var container = document.createElement("div");
        // use CLASS_VAR and 'options' in some way
        return container;
    }

    this.myContainer = privateMethod(this.options);
}

This is essentially the pattern that a portion of my code is using, but I just don't know if it's efficient or proper. Is this pattern a good idea, or are there more sensible/efficient/correct ways of achieving the same thing? In my actual code, there is more than one private function in doIt . Also, there is ~50 "class" variables in the actual code, so should I keep these in the global scope, or is there some way to make them private class variables as in Java private static final ?

Edited to reflect first comment

Answer 1

"@plalx well that's really what I was asking, I suppose. You see, I actually have 4 or 5 functions inside doIt (obviously its not called that) and those functions are a lot longer than the example. If I was to extract them all and dump everything into doIt it would be a bit of a mess."

Well, if the functions are only meant to be used inside doIt , you could do something like:

MyClass.prototype.doIt = (function() {

    function privateMethod(options) {
        var container = document.createElement("div");
        // use CLASS_VAR and 'options' in some way
        return container;
    }

    function someOtherPrivateMethod() {}

    return function () {
        this.myContainer = privateMethod(this.options);
    };
})();

Answer 2

In the example you provided, there aren't any 'real' private methods. The method 'privateMethod' is just a standard member of the 'doIt' method.

If you need to create real private members - The following is an excellent guide on Javascript Patterns (I recommend you start with the 'Revealing' pattern, and take it from there): Javascript Design Patterns