JavaScript is the essential programming language, not only on the client-side but also on the server-side. Unfortunately, the number of frameworks and libraries makes it very difficult to define a simple strategy for a company.

React, and Angular are currently the two highest options to style responsive Single Page Applications (SPAs).

The main difference being, Angular is a framework powered by Google, and React a javascript library introduced by Facebook to build dynamic user interfaces. With Angular, you've got less flexibility than React; the framework dictates how you make the apps and provides all the necessary tools to write down SPAs. 

React is a lightweight library that you can use to make SPAs. With React, you would like to settle on your libraries and learn them, and with Angular, they're included within the framework.

Let us discuss them in detail.

Angular

It is based on typescript, which is a superset of javascript. If you come from the Java world, learning Angular will be a cup of tea. It uses the same Object-oriented principles and patterns.

It is Portable. You'll use it for web apps and also mobile using Ionic or NativeScript. You'll have several other options:

• Easy to possess one code base for mobile, web and PWA, especially with Ionic.
• Lots of plugins and integrations.
• Better error handling.
• More complex and harder to learn.
• Complete Framework: Components, Dependency Injection, Forms, Routing.
• Easier to divide teams and roles (designer/developer).
• Suitable for large projects.

React

It is based on JavaScript and used widely for developing reusable HTML elements. It would be great if you've already got JavaScript developers within the team.

• Very fast. Outstanding Performance, better than Angular.
• Easy to learn.
• React uses the Virtual DOM. It is the abstract form of Real DOM. This results in building a dynamic UI with a better user experience.
• Code stability with one-directional data binding.
• Great for small and medium complex apps.
• Great for complex applications where the state is tough to manage.
• Harder to have a single code base.
• In general, it's costlier to deliver a project in React compared to Angular.
• Better integration with GraphQL.