Javascript Object Oriented Design - Javascript Module Pattern

The module pattern is an object-creation pattern designed to create singleton objects with private data.

Its format is shown as follows.


var yourObject = (function() { 
    // private data variables 
    return { //w w  w .  j  av  a  2  s. c  o  m
        // public methods and properties 
    }; 
}()); 

<p>For example: </p>

var book = (function() { 
    var version= 1; 
    return { 
        name : "Javascript", 
        getVersion: function() { 
            return version; 
        }, 
        publishNewVersion : function() { 
            version++; 
        } 
    }; 
}()); 

console.log(book.name);      
console.log(book.getVersion());  //Javascript

book.version = 2; 
console.log(book.getVersion());  //1

book.publishNewVersion(); 
console.log(book.getVersion());  //2

The code above generates the following result.

Example

The revealing module pattern arranges all variables and methods at the top and assigns them to the returned object.

We can write the previous example using the revealing module pattern as follows:


var book = (function() { 
    var version = 1; 
    function getVersion() { /*w  w  w  . jav  a  2  s  . c  om*/
        return version; 
    } 
    function publishNewVersion() { 
        version++; 
    } 
    return { 
        name : "Javascript", 
        getVersion: getVersion, 
        publishNewVersion : publishNewVersion 
    }; 
}()); 

console.log(book.name);      
console.log(book.getVersion());  //Javascript

book.version = 2; 
console.log(book.getVersion());  //1

book.publishNewVersion(); 
console.log(book.getVersion());  //2

The code above generates the following result.