What is RxJS?

 

What is RxJS?

The full form of RxJS is Reactive Extension for Javascript.

As per the official website of RxJS - RxJS is a library for composing asynchronous and event-based programs by using observable sequences. It provides one core type, the Observable, satellite types (Observer, Schedulers, Subjects) and operators inspired by Array#extras (map, filter, reduce, every, etc) to allow handling asynchronous events as collections

To manage the sequence of events RxJS combines the Observer pattern with the Iterator pattern and functional programming with collections

 

Observer Pattern:

It is a software design pattern in which an object called Subject maintains a list of its dependents called Observers. It works well for applications that expect real-time updates.

It is one to many patterns which are one Subject Many Observers.

When the subject is updated it will automatically fire an event and notify the observers of the state changes and it carries some data along with it.

 

                                            

 

 

 

Essential concepts of RxJS:

Observable:  Function that creates an observer

Observer: is an object includes next(), error()  & complete() methods and it listen to values delivered by Observables.

Subscription: it will subscribe to the Observable to get execute it. It is also used to cancel the execution.

Operators: Pure functions that dealing with collections with operations like map, filter, concat, reduce, etc.

Subject: Is an Observable multicast value to many observers i.e. one to  many.

Schedulers: controls the execution that when the computation should happen.