demo.js

1)
var Abc = function(aProperty,bProperty){
    this.aProperty = aProperty;
    this.bProperty = bProperty;
    this.init = function(){
        // Do things here.
    }
    this.init();
}; 
var currentAbc = new Abc(obj,obj);


2)
var Abc = function(aProperty,bProperty){
   function privateInit(){ console.log(this.aProperty);}   
   this.aProperty = aProperty;
   this.bProperty = bProperty;

   privateInit.apply(this);
};


3)
var Abc = function(aProperty,bProperty){
    this.aProperty = aProperty;
    this.bProperty = bProperty;

    //init
    (function () {
        // Perform some operation
    }.call(this));
}; 
var currentAbc = new Abc(obj,obj);