There are many concepts which Angular shares with React, Vue and other component-based JavaScript libraries/frameworks. However, when it comes to Angular, there is one big player in the game who is usually not present when using other frameworks, and that is RxJS.

Writing good quality Angular applications both in terms of performance, code readability, and reusability often requires having a good grasp of how RxJS works and how it can be utilized to create reactive data streams.

Luckily, there are some good and free online tutorials available. We recommend watching Acedemind's Understanding RxJS YouTube playlist. There is also a cool website called RxJS Marbles where you can explore many different RxJS operators and see what they do, in a visual way. Egghead.io has some great courses as well, for example RxJS Beyond the Basics: Operators in Depth and Build an Angular Instant Search Component.

We also recommend reading the official documentation pages related to Observables and RxJS:

• Observables
• The RxJS library
• Observables in Angular
• Practical observable usage
• Observables compared to other techniques

When reading/watching online tutorials please note that there have been some breaking changes in RxJS version 6—some of the APIs have changed (mostly the way we use operators), and many tutorials that were created earlier are now using older versions of RxJS (v5 or older). That being said, not much has changed conceptually, just the way you write some RxJS functionalities, so those tutorials should still be worth checking out.