Understanding the Evolution of AngularJS, Angular 2, Angular 4, and Angular 5

AngularJS, released in October 2010, pioneered the way for dynamic and powerful web applications. It was written in JavaScript by Google and marked a significant leap in the development of web frameworks. However, it was just the beginning of Angular's journey. In this article, we will delve into the differences between AngularJS, Angular 2 versions, and their unique features, advancements, and why developers might have chosen to focus on Angular 2 at a time when Angular 6 was on the horizon.

Introduction to AngularJS

AngularJS was the first version of the Angular framework, released on October 20th, 2010. It was developed by Google and written in JavaScript. AngularJS revolutionized web development by introducing declarative programming and a two-way data binding system, making it easier for developers to build dynamic web applications.

Breaking Changes and Angular 2

Angular 2 marked a significant evolution in the framework, breaking away from AngularJS. Released on October 23, 2016, it was a complete rewrite by Google developers, and developers had to learn a new architecture and syntax. Angular 2 introduced several key components that have become fundamental in modern web development:

Modules, Components, Directives, and Routing: Angular 2 introduced a new system of modules, components, directives, and routing, replacing the estraverse-based template used in AngularJS. These building blocks provide a more modular, scalable, and maintainable way to build web applications. Dependency Injection: Angular 2 comes with a built-in dependency injection system, which makes it easier to manage the dependencies of components seamlessly. Data Binding: Data binding in Angular 2 is more powerful and flexible compared to AngularJS, allowing for two-way data binding as well as one-way data binding through expressions in templates. HttpClient: Angular 2 introduced HttpClient, a smaller library for making HTTP requests, which is more robust and easier to use than the_PROVIDERS_ in AngularJS. Animations: While Angular 2 offers powerful animations, developers can choose to disable animations for performance optimizations.

Continuous Evolution: Angular 4 and Angular 5

Angular 4, released on December 13, 2016, was a straightforward improvement over Angular 2. It came with several features that made application development even more efficient and powerful:

HttpClient: Angular 4 further developed the HttpClient module, making it even smaller and more powerful for making HTTP requests. Router Lifecycle Events: Angular 4 introduced router lifecycle events, including guards and resolvers, which are essential for implementing complex navigation processes and data loading before routes are activated. Conditional Animations: Developers can now more flexibly control when animations are enabled or disabled, providing better performance and user experience.

Angular 5, released on November 1, 2017, built upon the improvements of Angular 4. It focused on performance and material design, offering further optimizations for the build process and enhancements in the Material Design library:

Build Optimization: Angular 5 provided tools and techniques to optimize the build process, making the application loading faster and more efficient. Material Design Improvements: Angular 5 incorporated improvements and enhancements to the Material Design library, providing better UX and a more polished look and feel for web applications.

Choosing Angular 2 in the Face of Angular 6

Sharad Jain's answer to Why are you learning Angular 2 if Angular 6 is about to be released? To be more stable.

When Angular 2 was introduced, it was a significant shift from the previous version. Angular 6, while more stable, came with a number of features and improvements that could take some time to fully implement in an existing project. This meant that developers might have opted for Angular 2 because it had a more stable release and a better-established ecosystem. Additionally, Angular 2 introduced fundamental changes that made the framework more robust and easier to manage in the long run.

The decision to use Angular 2 over Angular 6 might have been strategic, as it allowed developers to leverage the stable and widely adopted version of the framework at the time. This choice ensured that the project was built on a solid foundation and benefited from the robustness and stability of the framework before the more feature-rich version, Angular 6, was released.

Conclusion: Understanding the evolution of AngularJS, Angular 2, Angular 4, and Angular 5 is essential for any developer looking to join or contribute to an Angular project. Each version brought significant improvements and changes, catering to different needs and reinforcing Angular's position as one of the leading web application frameworks.