All Levels of Data Hiding in JavaScript

In the last post we talked about inheritance in pure JavaScript. Now we want to see how to implement data hiding (private, public, ...) in a JavaScript class.

 

var MyObj = (function() { // This is like a namespace
    var privateSharedVar = 'private shared value - (Java: private static)';

    function privateSharedFunction() {
        alert('Private shared function - (Java: private static)');
    }

    function MyObj() { // This is a public constructor
        var privateInstanceVar = 'Private instance value - Java: private';
        this.publicInstanceVar = 'Public instance value - Java: public';

        function privateInstanceFunction() {
           alert('Private instance function - (Java: private method)');
        };

        this.publicInstanceMethod = function() {
            alert('Public instance function - (Java: public method)');
        };
    }

    MyObj.prototype.publicSharedVar = 'Public shared value - (Java: public static)';

    MyObj.prototype.publicSharedMethod = function() {
        alert('Public shared function - (Java: Public static method)')
    };

    return MyObj;
})();

In this code we have all these levels:

• Private fields
• Public fields
• Private methods
• Public methods
• Private static fields
• Public static fields
• Private static methods
• Public static methods