What are the differences between AngularJS and Angular

AngularJS and Angular are two different frameworks developed by Google for building web applications, but they have significant differences due to their architectural and technological advancements. Here are the key differences between AngularJS (Angular 1.x) and Angular (Angular 2+):

1. Architecture:

   • AngularJS (1.x): Follows the MVC (Model-View-Controller) architecture where controllers manage the data and behavior of UI components.
   • Angular (2+): Follows a component-based architecture where applications are built as a hierarchy of components. Each component encapsulates a part of the UI and its logic.

2. Language:

   • AngularJS (1.x): Primarily uses JavaScript (ECMAScript 5).
   • Angular (2+): Written in TypeScript, which is a superset of JavaScript. TypeScript adds features like static typing, interfaces, enums, and decorators.

3. Rendering:

   • AngularJS (1.x): Uses two-way data binding through the "digest cycle" to automatically update the view when the model changes and vice versa.
   • Angular (2+): Still supports two-way data binding but emphasizes unidirectional data flow by default, using a more efficient change detection mechanism.

4. Dependency Injection (DI):

   • AngularJS (1.x): Has its own DI mechanism, but it's less standardized compared to Angular.
   • Angular (2+): Uses a hierarchical injector for DI, making it more robust and allowing easier testing and modularization of code.






5. Mobile Support:

   • AngularJS (1.x): Limited support for mobile development.
   • Angular (2+): Provides improved mobile support and performance optimizations, making it suitable for building progressive web apps (PWAs) and hybrid mobile applications.

6. Modularity:

   • AngularJS (1.x): Less emphasis on modularity, resulting in larger bundles and less flexibility in managing dependencies.
   • Angular (2+): Built with modularity in mind using NgModules. Applications are organized into modules, making it easier to manage dependencies and lazy load parts of the application.

7. Tooling and Ecosystem:

   • AngularJS (1.x): Limited tooling support and fewer third-party libraries compared to Angular.
   • Angular (2+): Extensive tooling support (Angular CLI, TypeScript support, etc.) and a vibrant ecosystem with a wide range of libraries and extensions.

8. Performance:

   • AngularJS (1.x): Performance improvements were made over time, but it can struggle with large-scale applications due to its digest cycle and two-way binding mechanism.
   • Angular (2+): Significant performance improvements with a more efficient change detection mechanism and improved rendering pipeline.

9. Backward Compatibility:

   • AngularJS (1.x): AngularJS applications require migration effort to upgrade to newer versions.
   • Angular (2+): Angular has a more modular and flexible architecture, making it easier to upgrade between versions with backward compatibility and clear migration paths.

In summary, Angular (Angular 2+) represents a complete rewrite of AngularJS (Angular 1.x), focusing on modern web development practices, performance improvements, TypeScript integration, and a component-based architecture. It addresses many of the limitations and challenges found in AngularJS, making it a more robust and scalable framework for building web applications.