Six years ago, Google was releasing AngularJS, a JavaScript based open-source front-end web application framework that developers have started to use to build mobile & desktop web applications. Angular has even a motto: “HTML enhanced for web apps!”, because it’s added to an HTML page with a <script> tag, extending its attributes with Directives, then it uses Expressions to bind data to HTML. Back in September 2014, version 2.0 of Angular was announced at the ngEurope conferences and Google has taken developers by surprise with controversial changes, and at the end of April, the JavaScript Framework moved from Alpha to Developer Preview, then in December, it moved again to Beta. Finally, after the first release candidate was brought in May, this year, the final version was published on September 14. Angular 2 was completely rewritten, and it promises to revolutionize enterprise app development.
When Angular 1 came six years ago, developers began building single-page applications which included interactive features that offered a real-time experience. The most popular products that were built from scratch with Angular are YouTube for PS3, weather.com, freelancer.com, Netflix, Tinder and many more. These dynamic web apps should have been static, but thanks to Angular, which allowed developers to use HTML as the template language, then extend its syntax, the application’s components were expressed clearly. Instead of writing code, Angular has simplified the development of the web app, as everything happens within the browser, because the code is eliminated with data binding and dependency injection.
By de-emphasizing explicit DOM manipulation, Angular improves app’s testability and performance. As for the design goals, according to Wikipedia, they include: decoupling DOM manipulation from application logic; decoupling the client side of an application from the server side; and providing structure for the journey of building an application. The MVC pattern is implemented to separate presentation, data, and logic components, and server-side services are brought to client-side web applications using dependency injection.
Angular 1’s core features are: Data-binding, Scope, Controller, Services, Filters, Directives, Templates, Routing, Model View Whatever, Deep Linking and Dependency Injection.
Scope
If you’re a beginner and this term is unfamiliar to you, you should know that is has an important role, as it’s the connection point between the HTML (view) and the JavaScript (controller). According to the ECMA-262 specification, scope is defined as “a lexical environment in which a Function object is executed in client-side web scripts; akin to how scope is defined in lambda calculus.” Google has explained that the characteristics of Scope include providing APIs ($watch) “to observe model mutations”; providing APIs ($apply) “to propagate any model changes through the system into the view from outside of the “Angular realm” (controllers, services, Angular event handlers).
Related blog: AngularJS and Ionic for App Development: The Ultimate Combination
Differences Between Angular 1 and Angular 2
The changes that were made to Angular 2, which was rewritten, not upgraded, include: Mobile development, Modularity and Modern browsers only. Also, Google recommend developers to use Microsoft’s TypeScript language, which also brought improvements such as: Class-based Object Oriented Programming, Static Typing, Generics and Lambdas. TypeScript is a superset of ECMAScript 6, and the new version of Angular has adopted some of ES6’s features: Iterators, For/Of loops, Python-style generators and Reflection.
Angular 2’s other new features include Dynamic loading, Asynchronous template compilation, Simpler Routing, Diary.js logging and reactive programming support using RxJS. Google has also improved dependency injection, allowing developers to name dependencies, while controllers and $scope can be replaced with components and directives.
Why You Should Build Apps With Angular 2?
- The testability of the code will be improved by decoupling DOM manipulation from app logic
- The client side will be decoupled from the server side, so development work will progress in parallel
- The amount of JavaScript coding will be reduced, and it will be easier for you to see the potential of the application
- You won’t need to programmatically manipulate the DOM
- The code will not describe the implementation details, but only the overall flow of the application
- Angular will auto-inject services into the application and you will be able to develop features quickly. Google promises that you will get full control over the initialization process in automated tests
Angular 2’s Weaknesses
Developers have different coding styles and until they get used to Angular 2, they will struggle a little to understand how to integrate different components. You will really need to learn the code, to be ready to master the application and evolve the project over time, but at the same time, you mustn’t make the app too complex, with big data grids and lists, because if you’ll have over 2000 watchers, they will experience a UI lag.
Conclusion
Many companies have adopted Angular and the popularity of this “superheroic JavaScript framework” has exploded shortly after it was released. AngularJS Developers are using it because it offers Two-way data-binding, Directives, Client side MVC framework, Dependency Injection, Filters and Templating, and now that the second version of the platform was launched with new features, developers will build web apps much easier.
