Programming & technology

filter(): runs a function on every item in the array and returns an array of all items for which the function returns true.

Syntax:

var filteredArray = array.filter(callback[, thisObject]);

var arrayObj = [
            {"uuid": "C3EF0958-F530-0001-4793-1A3917C011DB","name" : "borey", "position": "developer"},
            {"uuid": "f47ac10b-58cc-4372-a567-0e02b2c3d479", "name": "sok", "position": "designer"},
            {"uuid": "C3EF0948-3F50-0001-8E28-C560102CD090", "name": "seiha", "position": "developer"},
            {"uuid": "C3EF094D-CD90-0001-3567-139E1BF01B14", "name": "dara", "position": "manager"},
            {"uuid": "C3EF0953-FCD0-0001-A745-1C3019401ED7", "name": "meta", "position": "developer"}
            ];

var updateValue = function(uuid, newObj){
    var obj = arrayObj.filter(function(obj){ return obj.uuid == uuid;  })[0];
    obj.uuid = newObj.uuid;
    obj.name = newObj.name;
    obj.position = newObj.position;
};

var displayArrayObjectValue = function(arrayObject){
    var length = arrayObject.length;
    for( var i = 0; i < length; i++){
        console.log(arrayObject[i].uuid + ' '+arrayObject[i].name + ' '+arrayObject[i].position);
    }
}

var updatedObjValue = {"uuid": "3EF099C-4940-0001-A0F8-F92E1FC8C430", "name": "ibo", "position": "lead developer"}

console.log('before change: ');
displayArrayObjectValue(arrayObj);

updateValue("C3EF0958-F530-0001-4793-1A3917C011DB", updatedObjValue);

console.log('after change: ');
displayArrayObjectValue(arrayObj);

The code above will update the value of object which has uuid = “C3EF0958-F530-0001-4793-1A3917C011DB”

Here’s how we create javascript object using Javascript Object Notation (JSON). After the code below is executed, it would show alert windows with text “Borey Lim”

//script to demonstrate creating object in javascript using JSON

var objectDemo = {
	firstName: "",
	lastName: "",
	displayName : function(){
		alert(this.firstName + " " + this.lastName);
	}
}

objectDemo.firstName = "Borey";
objectDemo.lastName = "Lim";
objectDemo.displayName();

Cloud computing is a style of computing in which dynamically scalable and often virtualised resources are provided as a service over the Internet.

A research paper released on October 8th, 2007 by Greg Boss, Padma Malladi, Dennis Quan, Linda Legregni, Harold Hall from IBM states: “Cloud computing is a term used to describe both a platform and type of application. A cloud computing platform dynamically provisions, configures, reconfigures, and deprovisions servers as needed. Servers in the cloud can be physical machines or virtual machines. Advanced clouds typically include other computing resources such as storage area networks (SANs), network equipment, firewall and other security devices.

Cloud computing also describes applications that are extended to be accessible through the Internet. These cloud applications use large data centers and powerful servers that host Web
applications and Web services. Anyone with a suitable Internet connection and a standard browser can access a cloud application.”

Simply said, if you don’t need to have operating system & other software application installed on your device, what you need is a device that support web browser. You can use the application through web browser. One of the good example is eyeOS. eyeOS is one of cloud OS  out there. It’s an opensource project. After spent some hours playing around with it, I’ve got the feeling that i’m in love with it. Here is the website of eyeOS: http://www.eyeos.info/

Inheritance in javascript can be implemented easily using the concept of mixin. Below is an exmple to demonstrate javascript inheritance:

ClassA = function(){
	this.display = function(){
		console.log("here's a display function in ClassA");
	}

	this.str = function(){
		return "string in ClassA";
	}
}

ClassB = function(){
	ClassA.call(this);

//overriden method
	this.str = function(){
		return "string in ClassB";
        }
}

//instantiate object of ClassB
obj = new ClassB();

//calling display method from ClassA
obj.display();

//this will invoke str method in ClassB NOT in ClassA
console.log(obj.str());

C++ allows developers to use multiple inheritance. Unlike C++, Ruby only allows developers to use single inheritance. But Ruby has mixin functionality, which allows code to be included from other modules.

Here’s sample code to demonstrate mixin:

module MixinFirst
	def mixin_first_display
		puts "This is mixin first"
	end
end

module MixinSecond
	def mixin_second_display
		puts "This is mixin second"
	end
end

class Base
	def inheritance_display
		puts "This is inheritance"
	end
end

class Child < Base
	include MixinFirst
	include MixinSecond
end

child = Child.new
child.mixin_first_display
child.mixin_second_display
child.inheritance_display

Sample result: