Extend.js

// extend.js
// Written by Andrew Dupont, optimized by Addy Osmani
 
function extend( destination, source ) {
 
    var toString = Object.prototype.toString,
        objTest = toString.call({});
 
    for ( var property in source ) {
        if ( source[property] && objTest === toString.call(source[property]) ) {
            destination[property] = destination[property] || {};
            extend(destination[property], source[property]);
        } else {
            destination[property] = source[property];
        }
    }
    return destination;
 
};
 
console.group( "objExtend namespacing tests" );
 
// define a top-level namespace for usage
var myNS = myNS || {};
 
// 1. extend namespace with a "utils" object
extend(myNS, {
        utils:{
        }
});
 
console.log( "test 1", myNS);
// myNS.utils now exists
 
// 2. extend with multiple depths (namespace.hello.world.wave)
extend(myNS, {
                hello:{
                        world:{
                                wave:{
                                    test: function(){
                                        //...
                                    }
                                }
                        }
                }
});
 
// test direct assignment works as expected
myNS.hello.test1 = "this is a test";
myNS.hello.world.test2 = "this is another test";
console.log( "test 2", myNS );
 
// 3. what if myNS already contains the namespace being added
// (e.g. "library")? we want to ensure no namespaces are being
// overwritten during extension
 
myNS.library = {
        foo:function () {}
};
 
extend( myNS, {
        library:{
                bar:function(){
                    //...
                }
        }
});
 
// confirmed that extend is operating safely (as expected)
// myNS now also contains library.foo, library.bar
console.log( "test 3", myNS );
 
 
// 4. what if we wanted easier access to a specific namespace without having
// to type the whole namespace out each time?
 
var shorterAccess1 = myNS.hello.world;
shorterAccess1.test3 = "hello again";
console.log( "test 4", myNS);
 
//success, myApp.hello.world.test3 is now "hello again"
 
console.groupEnd();