RxJS Tutorial - javatpoint

RxJS tutorial provides basic and advanced concepts of Reactive Extension for Javascript and Reactive programming. In this tutorial, you will get an overview of Reactive programming, Reactive extension for JavaScript, and its programming concepts, functionalities of RxJS etc. in an easy and simple way. Our RxJS tutorial is designed for beginners and professionals.

RxJS is a JavaScript library that can used with other JavaScript libraries and frameworks such as Angular, ReactJS, Vue.js, Node.js etc. It is supported by JavaScript and also with TypeScript.

Our RxJS tutorial includes all topics of reactive programming, RxJS Latest Updates, RxJS Observables, RxJS Operators, RxJS working etc.

Introduction to RxJS

RxJS is an acronym that stands for Reactive Extension for JavaScript. It is a JavaScript library that is used to work with Reactive programming that deals with asynchronous data calls, callbacks and event-based programs. RxJS can be used with other JavaScript libraries such as Angular, ReactJS, Vue.js, Node.js etc. It is supported by JavaScript and also with TypeScript.

What is Reactive Programming?

Reactive Programming is a declarative programming paradigm that concerns data streams and the propagation of changes. It is another different way to built software applications. In Reactive Programming, we can easily express static such as arrays or dynamic such as event emitters data streams. It also specifies that an existed inferred dependency within the associated execution model can facilitate the automatic propagation of the changed data flow.

For example:

In the imperative programming declaration, you have seen that a:=b+c would simply mean that a is being assigned as the result of b+c in the instant the expression is evaluated. You can change the values of b and c later, and there would be no effect on the value of a. On the other hand, in reactive programming, the value of a is automatically updated whenever the values of b or c is changed, without the program having to re-execute the statement a:=b+c. In simple means, it determines that a is always assigned with updated values of b+c.

What is RxJS?

The official website of RxJS has defined it as 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.

RxJS is a JavaScript library that has introduced the concept of "reactive programming" to the web. In general terms, you can say that RxJS is a Reactive programming language. It provides way to write assembly lines in your software applications. It facilitates you to write software that can be reusable, configurable, and asynchronous.

Features of RxJS

Following is the list of essential concepts or primary features of RxJS that are used to solve async event management:

Observable

The observable is used to represent the idea of an invokable collection of future values or events. It can be defined as a function that creates an observer and attaches it to the source where values are expected. The observable examples are clicks, mouse events from a dom element or an Http request, etc.

Observer

It is a collection of callbacks that are used to specify how to listen to values delivered by the Observable. It can be specified as an object with next(), error() and complete() methods, that will be executed when you have to interact with observable.

Subscription

It is used to represent the execution of an Observable. It is primarily used to cancel the execution. For example, when the observable is created, you have to subscribe to it to execute the observable. It can also be used to cancel the execution.

Operators

Operators are simple functions used to enable a functional programming style to deal with collections with operations like map, filter, concat, flatMap, etc. It takes observable as input and gives the output also in the form of observable.

Subject

A subject is equivalent to an EventEmitter and used to multicast a value or event to multiple Observers. For example: Consider a button with an event listener; the function attached to the event will be called whenever the user will click on the button.

Schedulers

The Schedulers are centralized dispatchers that are used to control concurrency. They are used to control the execution when the subscription has to start and notified.

Prerequisite

Before learning RxJS tutorial, you must have the basic knowledge of JavaScript, TypeScript, Reactive programming and the some frameworks of JavaScript such as Angular, ReactJS, Vuejs, nodejs etc.