Aspect Oriented Programming in Javascript (ES5+\Typescript)

world evolved very fast in the last 8 years. But we’re stuck in some problems that I’ll try to explain in this article and provide a solution. Javascript OOP try to face up development process by the separation of concerns into different entities. Deconstructing problem domain is a must to organize our code. Also using SRP ( ) and IoC ( ). Single Responsibility Principle Inversion of Control . Often we’re used to copy and paste code blocks to make things work. Hope you’re agree with me when I say that is ugly and not easy to read. But sometimes OOP is just not enough How many times you were trying to figure out “what does this method really do??” because infrastructure code was scattered across and hiding the real purpose, don’t you?: Above mentioned. The purpose of that method (::doCheckout) is asign shippingDetails to instance property and then POST it to the server. To achieve this nowadays we’re used to write infrastructure code, for example to validate method params, then make an AJAX request ( ) and so on. copy and paste code from other place and change a few variables… If you have to repeat this each time you face this situation you’re not doing your best. Less code is better than clean code Of course this is somehow an example, real world problems aren’t easy. We want to achieve this, don’t you? ( ) skip to library Introducing AOP is about smash CCC ( ). Aspect Oriented Programming Cross-cutting concerns Not all infrastructure code is CCC, but some do. If we’re pasting the same code changing a few variables or arguments each time to fit the current context. That code is a prime candidate for AOP. That code can be abstracted and prepared to be injected or some method and be able to receive the method/instance context to perform the operation like if it (the code) was here. after before This is not magic, just IoC. In a nutshell, AOP is a toolkit against repetition If you’re yet not able to understand this article , then go cry. think about console.log placed everywhere Featuring KAOP/KAOP-TS I built this library by trying to implement OOP features in ES5. For example allowing inheritance without getting your hands dirty in prototypes and overriding parent methods. In the code below I’m declaring class extending class overriding its constructor: Programmer Person . But when I succeeded got realized that “override” is just a Modern versions of Javascript do this code block injected before a method execution which takes the context of the annotated method to do some stuff… which is an interesting technique that remind me to AOP Alliance or Spring in Java . Above example is an implementation of “override” advice which is placed before the method we’re used to override. When you’re about implement an (which is an abstracted code block) you’re used to get method or instance context. keyword is the scope metadata, which contains several properties to allow : advice , meta reflection AOP is about define and apply patterns/behaviors Instead of copy and paste blocks of code, with KAOP you can take that code block, making more abstract and then inject it where it is needed. KAOP enables a way to build your code that allows which aims for**:** declarative programming “Remove side effects by describing , rather than describe to accomplish it as a sequence of the language ”. the program must accomplish in terms of the what problem domain how programming primitives Even you’re capable to build on your own. Because both AOP and DI are Dependency Injection reflection techniques : Previous example consists on Resource class which takes a nodeProvider which if injected into a constructor to each resource subclass and all of them will listen for request having their own . So simply we’re giving the responsibility to listen requests per instance and code is well organized and is easy to extend within OOP patterns. provides a singleton of node http server instance resourceIdentifier If you liked the article check this example with Angular 2+ app Done for today, I highly recommend . if you care about this topic you to check this Any contributions are welcome: _kaop - Advanced OOP Library with createClass, inheritance, providers, injectors, advices which enables handy Inversion…_github.com k1r0s/kaop _kaop-ts - Simple Yet Powerful Library of ES2016 Decorators with Strongly typed method Interceptors like BeforeMethod…_github.com k1r0s/kaop-ts is how hackers start their afternoons. We’re a part of the family. We are now and happy to opportunities. Hacker Noon @AMI accepting submissions discuss advertising & sponsorship To learn more, , , or simply, read our about page like/message us on Facebook tweet/DM @HackerNoon. If you enjoyed this story, we recommend reading our and . Until next time, don’t take the realities of the world for granted! latest tech stories trending tech stories