Framework vs. Library
Comparing Angular and React is not as straightforward since the first one is a UI component lightweight library and the second is a fully-featured framework. This means that with React you have more freedom to choose which libraries you use but you need to maintain the migrations and updates by yourself. On the contrary, Angular provides more functionalities right out of the box – you have less flexibility but do not have to think about which libraries to use for certain features.
Google vs. Facebook
Angular was released in 2016 and is created and maintained by Google. It is a rewrite of AngularJS and is used by Google in many of its applications, including Google Analytics, Google Adwords, and the Google Cloud Platform.
React is developed by Facebook and was released in 2013. Facebook used it in its products such as Instagram and WhatsApp.
Using React means that you need to know JSX – a template language that combines markup and logic in the same file. Thus you can write markup directly into the JS code and in case you make a mistake in the markup, the compiler will send out an error so you can catch mistakes and typos quickly.
You do not need to learn JSX for Angular, but you need to know TypeScript, making your code easier to debug and more predictable.
React uses one-way data binding, which means that when you change the model state, the update is applied to the UI element, but when you update the UI element, the model state does not change.
On the contrary, Angular uses two-way binding, and when you update the model state, it will change the UI and vice versa. This means less code and less complicated data.
Regular vs. Virtual DOM
Angular uses a regular DOM while React uses a virtual DOM – one of the top reasons it is so fast. A regular DOM requires updating the entire tree structure of HTML tags in case of any changes, while a virtual DOM is an abstraction of the HTML DOM, and any changes in it can be compared to the real DOM, which will change only where required.
Angular is significantly more difficult to learn because it is a fully-fledged MVC framework. It requires learning TypeScript, modules, directives, components, decorators, services, pipes, dependency injection, templates – and this is only the start. When you advance, you need to be familiar with zones, change detection, RxJS, and AoT compilation.
On the contrary, React is a lightweight UI library and requires you to become familiar with JSX, a state management library, and a router library. In addition, you need to know how to write components, how to use props for configuration, and how to manage the internal state.
In conclusion, React provides more freedom, but Angular enforces a lot of best practices. Both are stable and mature, backed up by large and active communities.