AngularJS

AngularJS is an open-source JavaScript framework used to build a dynamic web application. Angular is a structural framework for developing dynamic web apps. It allows developers to use HTML as a template language and allows HTML’s syntax to express the application’s components briefly and clearly. AngularJs is maintained by Google.

Features of AngularJS

1. Model View Controller(MVC) Framework: MVC is a software design pattern used for developing web applications. The working model of AngularJS is based on MVC patterns. The MVC Architecture in AngularJS is easy, versatile, and dynamic. MVC makes it easier to build a separate client-side application.
2. Data-binding: Angular uses the two-way data binding method. It helps you to ensure that the model state automatically changes when any change is made.
3. Services: AngularJS has several built-in services such as $http to make an XMLHttpRequest.
4. User interface with HTML: In AngularJS, User interfaces are built on HTML. It is a declarative language which has shorter tags and easy to comprehend. It provides an organized, smooth, and structured interface.
5. Dependency Injection: AngularJS has a built-in dependency injection subsystem that helps the developer to create, understand, and test the applications easily.
6. Routing: Routing is the transition from one view to another view. Routing is the key aspect of single page applications where everything comes in a single page. Here, developers do not want to redirect the users to a new page every time they click the menu. The developers want the content load on the same page with the URL changing.
7. Active community on Google: AngularJS provides excellent community support. It is Because Google maintains AngularJS. So, if you have any maintenance issues, there are many forums available where you can get your queries solved.

ReactJS

ReactJS is an open-source JavaScript library used to build a user interface for Single Page Application. It is responsible only for the view layer of the application. It provides developers to compose complex UIs from a small and isolated piece of code called “components.” 

it is developed and maintained by Facebook. Facebook and Instagram uses React js

Features of ReactJS

1. JSX: JSX is a JavaScript syntax extension. The JSX syntax is processed into JavaScript calls of React Framework. It extends the ES6 so that HTML like text can co-exist with JavaScript React code.
2. Components: ReactJS is all about components. ReactJS application is made up of multiple components, and each component has its logic and controls. These components can be reusable, which help you to maintain the code when working on larger scale projects.
3. One-way Data Binding: React language uses one-way data binding, which means that the Ul elements can’t be changed without updating the corresponding model state.
4. Virtual DOM: A virtual DOM object is a representation of the real DOM object. Whenever any modifications happen in the web application, the entire UI is re-rendered in virtual DOM representation. Then, it checks the difference between the previous DOM representation and new DOM. Once it has done, the real DOM will update only the things that are changed. It makes the application faster, and there is no wastage of memory.
5. Simplicity: ReactJS uses the JSX file, which makes the application simple and to code as well as understand. Also, ReactJS is a component-based approach that makes the code reusable as needed. It makes it simple to use and learn.
6. Performance: ReactJS is known to be a great performer. The reason behind this is that it manages a virtual DOM. The DOM exists entirely in memory. Due to this, when we create a component, we did not write directly to the DOM. Instead, we are writing virtual Components that will turn into the DOM, leading to smoother and faster performance.

Disadvantages of Angular JS

1. Despite a comprehensive and clear manual, steep learning curve and complexity are named among the main weak points of Angular.js. Like any other client-side rendering technology in javascript framework comparison list, programmers should place special emphasis on security to make apps reliable and safe. Though, with the introduction of Angular Universal and pre-rendering options in ng2 this issue was defused.

Disadvantages of React JS

1. First of all, it’s worth mentioning that reactJS is not a full-scale framework and for this very reason integration of the UI library into a common MVC framework requires deeper programming knowledge. 

1. Apart from the pros and cons of React JS, we should also mention Flux that is frequently applied for adding a structure and architecture to react apps. Usage of both technologies can become a challenge for non-experienced programmers, as it lacks structured and comprehensive documentation or guidance.

Conclusion

Both React and AngularJS are great options with respect to single-page applications. However, both of them are also entirely different instruments. There might be statements like React is better than Angular or also vice versa.

React and Angular offer completely diverse approaches to web application development for startup, small and midmarket businesses. Both technologies are powerful and flexible, while none of them is worse or better than the other. Depending upon custom app goals and particular system constraints, developers can run from ng2 to React, and back.