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Encapsulation in object oriented javascript

While this is no longer late breaking news, it bears repeating: JavaScript is a powerful object oriented language, capable of being used to build sophisticated applications on both the client and the server. However, the more sophisticated the implementation, the bigger our responsibility to create maintainable and flexible code.

Encapsulation includes the idea that the data of an object should not be directly exposed. Instead, callers that want to achieve a given result are coaxed into proper usage by invoking methods rather than accessing the data directly.

Everything looks OK, so far. We created the object, printed and changed the fullName without any issues. However, imagine that someone accidentally misuses this object, and sets the fullName to an invalid value, such as a number:.

This is perfectly legal. As far as JavaScript is concerned, a variable can accept any type of data as its value. However, we may want to restrict the range of valid characters to satisfy how we use the fullName in our application. The goal of this method is to ensure no numeric characters are included when the name is set by the caller. Looks better. The end goal here is to prevent callers from accessing fullName directly, which is where encapsulation comes into the picture.

This is where closures help us out. Here we have a function which is hiding the fullName variable from the outside world. The inner object theObjhowever, can access fullName :. But how do we expose the inner object to the outside world?

Thankfully the solution is simple: return the inner object when the anonymous function is called, and assign it to the outside variable person. The only real changes needed are with lines 6 and The trick is to remember to call the anonymous function immediately after its definition, and assign the return value the inner object to the outside variable personrather than simply assigning the anonymous function itself to the outside variable.

This is done by using the invocation operator,at the end of the function. Great post, Jason! Then I have to put my OO hat on and refactor. Thanks Tom! I have quite a bit of experience with QUnit from the jQuery team.

encapsulation in object oriented javascript

I am coming from a very procedural C kind of programming and just started to understand more the power of javascript. This post is very well explained and helpful.However, the higher the complexity in the implementation, the better maintainable and flexible code is needed to tackle the situation.

Encapsulation, one of the principles of Object-Oriented Programming is the key to achieve such goals.

The Flavors of Object-Oriented Programming (in JavaScript)

By definition Encapsulation in JavaScript is a process of binding the data with the functions which act upon the data. Encapsulation allows us to control and validate the data. In JavaScript, variables resemble data. Encapsulation means information hiding i.

encapsulation in object oriented javascript

This will help restrict the unauthorized use of the variables. Instead, if the callers want to achieve a defined result it should use the public method or public entities inside the object to access the private variables of the object.

Everything looks fine in the above example. We created the object, printed its attribute value and modified it. But the problem seems to arise when some user tries to set an integer value to the name attribute. As far as JavaScript is concerned this is completely legal as in JavaScript a variable can accept any type given to it. In order to rectify this, we need to set the range of valid characters that can be set to the attribute name of the object.

The simple solution for this would be. The above example applies the validation but still has some faults as if the caller access the name directly, he can still change it.

Encapsulation helps it out. This can be solved by the concepts Function Scope and Closures. Any Variable which is written inside the code block of the functions remains hidden from outside. For this Closure will help. In simple words, closure gives access to a local variable of a function to be used by another function inside a parent function. Here we have a variable name hiding inside the function setName from the outside world. But the inner object myObjcan access it:. Now we have used the concept of closure, the inner object myObj can be accessed by both the functions.

But still, there is a fault to access the inner object. Above we have seen employee. Hence we need to return the inner object whenever the anonymous function is called and assign it to an outside variable.

The main advantage of using encapsulation in JavaScript is to provide security to the data. Other benefits of encapsulation include:.

Encapsulation is the tool in JavaScript which can be used to make the complex operation easy and manageable with making the overall application secure and easy to work. This is a guide to Encapsulation in JavaScript. Here we discuss the working of encapsulation in javascript along with concepts and advantages.

You may also look at the following articles to learn more.Encapsulation is one of the main concepts in object oriented programming. It allows an object to group both private and public members under a single name. All the object oriented programming languages support this.

Since JavaScript is also an object oriented programming language, it supports it too.

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In this article, we will see how to achieve encapsulation in JavaScript by creating a simple object named CssManager that helps to dynamically add, remove, or swap a style-sheet. Now you can wrap all the classes and objects related to Managers in a single namespace. In JavaScript, an object acts much like an associative array, i. The key is a property or a method. In addStyleSheetwe will do the following things: dynamically create a link element, set its attributes, and append to the head section.

In removeStyleSheetwe query for the particular stylesheet element link and remove it completely from DOM. While in swapStyleSheetwe are calling the other two methods to replace an existing stylesheet with a new one. So far, all the methods created are public. I would like to add two private members for the sake of the article. The first one is a variable that has the reference to the document object. The second one is a method that sets multiple attributes to the link element at once instead of calling setAttribute multiple times.

Unlike other languages, we can't easily mark members as public or private in JavaScript. To create private members, we have to use Closures. Closures help to create a private space. We are not going to see what closures are here, but let's see how they help to create private members. What we have done is created a Closure that looks like a self executing anonymous function that returns the public methods we added earlier. The pair of parentheses at the end makes the code get executed automatically.

All the members returned by the return statement are public, while the ones that come before are private. Our CssManager is ready! That's all! We have done it!! Thanks for reading this. If you feel this article is helpful to you, don't forget to vote. Please check out the attached sample code that shows how the CssManager helps to dynamically change the theme of a page.

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Encapsulation

Search within: Articles Quick Answers Messages. Tagged as ASP.Hi folks, here goes a quick post regarding the most important and frequently used concepts of advanced JavaScript Objects are key concepts of JavaScript, so in just a bit we'll get into some code to help us better understand these concepts. We create objects with methods, properties, and attributes.

See the original article here. Web Dev Zone. Thanks for visiting DZone today. Edit Profile. Sign Out View Profile. Over a million developers have joined DZone. Check out this quick post on the basics of objects, encapsulation, and abstraction in object-oriented JavaScript. Examples are included.

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Like Join the DZone community and get the full member experience. Join For Free. JavaScript is designed on a simple object-based paradigm. An object is a collection of properties, and a property is an association between a name or key and a value. In addition to objects that are predefined in the browser, you can define your own objects. This chapter describes how to use objects, properties, functions, and methods, and how to create your own objects.

So conceptually we can say that, you can define and create your own objects. Opinions expressed by DZone contributors are their own. Web Dev Partner Resources. Let's be friends:.The JavaScript Encapsulation is a process of binding the data i. It allows us to control the data and validate it.

To achieve an encapsulation in JavaScript:. Let's see a simple example of encapsulation that contains two data members with its setter and getter methods. JavaTpoint offers too many high quality services. Mail us on hr javatpoint.

Please mail your requirement at hr javatpoint. Duration: 1 week to 2 week. JavaScript Tutorial. JS form validation JS email validation.

JavaScript Encapsulation

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Angular 7. Compiler D. Software E. Web Tech. Cyber Sec. Control S. Data Mining. Javatpoint Services JavaTpoint offers too many high quality services. To achieve an encapsulation in JavaScript: - Use var keyword to make data members private. Use setter methods to set the data and getter methods to get that data. Read Only - In this case, we use getter methods only.As JavaScript is widely used in Web Development, in this article we would explore some of the Object Oriented mechanism supported by JavaScript to get most out of it.

How they differ from other languages? A class can have many Object, because class is a template while Object are instances of the class or the concrete implementation. Before we move further into implementation, we should know unlike other Object Oriented Language there is no classes in JavaScript we have only Object. The class syntax is not introducing a new object-oriented inheritance model to JavaScript.

JavaScript classes provide a much simpler and clearer syntax to create objects and deal with inheritance. Output: Traditional Way. Hence, we would be using ES6 in all our examples. Encapsulation — The process of wrapping property and function within a single unit is known as encapsulation. We are working with an Objects interface without considering the implementation details.

Object-Oriented JavaScript: Objects, Encapsulation, and Abstraction (With Examples)

Sometimes encapsulation refers to hiding of data or data Abstraction which means representing essential features hiding the background detail. Inheritance — It is a concept in which some property and methods of an Object is being used by another Object. Note: The Person and Student object both have same method i. Method Overriding allows method in a child class to have the same name and method signature as that of a parent class.

In the above code, super keyword is used to refer immediate parent class instance variable. This article is contributed by Sumit Ghosh.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. Writing code in comment? Please use ide. Skip to content. Related Articles. Object — An Object is a unique entity which contains property and methods. The characteristics of an Object are called as Property, in Object Oriented Programming and the actions are called methods.

An Object is an instance of a class. Objects are everywhere in JavaScript almost every element is an Object whether it is a function,arrays and string.

encapsulation in object oriented javascript

Note: A Method in javascript is a property of an object whose value is a function. Recommended Articles. What is the difference between Object. Article Contributed By :. Current difficulty : Easy.Learn Development at Frontend Masters. Which methods should I use? Object-Oriented Programming is a way of writing code that allows you to create different objects from a common object.

The common object is usually called a blueprint while the created objects are called instances. Each instance has properties that are not shared with other instances. For example, if you have a Human blueprint, you can create human instances with different names.

The second aspect of Object-Oriented Programming is about structuring code when you have multiple levels of blueprints.

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This is commonly called Inheritance or subclassing. You can create an instance with the new keyword. As in, Classes are an easier way of writing Constructor functions. Notice the constructor function contains the same code as the Constructor syntax above? We need to do this since we want to initialize values into this. More on this later under Inheritance. We have a lot more to cover. Classes begin to shine later. In OLOO, you define the blueprint as a normal object. You use Object.

After creating the instance, you need to run your init function. You can chain init after Object. Factory functions are functions that return an object. You can return any object.

You simply call the function. If you want to declare a property directly on an instance, you can write the property inside the constructor function. Make sure to set it as the property for this.

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Methods are commonly declared on the Prototype because Prototype allows instances to use the same method. You need another tool. You write the method after constructor like a normal function.

You just write more functions. You use the same process for declaring properties and methods on an instance. You assign them as a property of this. You cannot declare methods on the Prototype when you use Factory functions. Should you declare properties and methods directly on the instance? Or should you use prototype as much as you can? If you declare properties and methods on instances, each instance will take up slightly more memory.


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