AngularJS is an open source framework for building client applications in HTML and JavaScript / TypeScript. The framework is used to solve complexity of web development as it combines declarative templates, dependency injection, end to end tooling, and integrated best practices.

ReactJS is also an open source JavaScript library that is used for building user interfaces especially for single page web page. React makes us able to create reusable UI elements. Design simple views for each state in your application, and React will efficiently update and render just the right components when your data changes. Declarative views make your code more predictable and easier to debug. The framework is fully component-based. You can build encapsulated components that manage their own state, and then compose them to make complex UIs. Since component logic is written in JavaScript instead of templates, you can easily pass rich data through your app and keep state out of the DOM.

Now come to the difference between them, AngularJS vs ReactJS

The main difference between them is that they lie in state management. By default, the AngularJS is featured with data binding bundled and other side; React is augmented by Redux to perfect data flow with immutable data.

Scalability 

ReactJS is testable and it is also scalable whereas, AngularJS is only scalable.

Computed Properties 

As far as performance is concerned, plain getters in Angular are out of the scenario because they get called on each render. It is however possible to use BehaviorSubject from RsJS, as it serves the purpose. React allows the use of @computed from MobX – achieving the same objective but with a nicer API.

Dependency Injection

Dependency Injection is a software design pattern in which components are given their dependencies instead of hard coding them within the component. AngularJS provides a supreme Dependency Injection mechanism. It provides following core components which can be injected into each other as dependencies. When you have Angular background and you switch to React, you may miss the way how it handles dependencies.

Simplicity + Code length

ReactJS is mostly used for its quite easy and simple code to understand but developers could take time to set up a project in React. Whereas, Angular is not simple by any means. Its inherent complexity sometimes causes confusion and Angular specific 3rd party libraries and syntax.

Verdict:

ReactJS and AngularJS both are known as the best open source framework for web application development companies, small and medium enterprises. Overall, both front end framework offers best developing services. Many top AngularJS Development companies deal in both.