Introduction to RxJS - Extensions for JavaScript Reactive Streams » grokonez

https://grokonez.com/frontend/introduction-to-rxjs-javascript-reactive-stream

Introduction to RxJS – Extensions for JavaScript Reactive Streams

Reactive Extensions for JavaScript (RxJS) is a precise alternative for callback or Promise-based libraries. It treats any ubiquitous source of events in the exact same manner, whether it is reading a file, making an HTTP call, clicking a button, or moving the mouse. RxJS is built on top of the pillars of functional and reactive programming, as well as a few popular design patterns such as Observer and Iterator.

Everything - just like a Stream

To work with RxJS, we should think in terms of streams. The image below shows a simple stream (or pipeline) approach to handling data:

• Producer is data source that produces various forms of data to be consumed.
• Pipeline is series of logic blocks that will be executed in order when data becomes available. The data (stream of asynchronous data) are filtered and processed in different ways so that they can be more easily consumed by Consumer.
• Consumer subscribes to (or listen for) Producer’s events and will do something with (consume) received data.

Any data point that holds one or more values, from a single integer to bytes of data, can be applied to the concept of a stream. Streams originate from a Producer, where data flows through a pipeline, arriving at a Consumer.

For example, we have set of operations (filter, map) that occurs between the creation of the Producer of the stream (the array) and the Consumer (the function that logs to the console):

We can create streams from static data sources: numbers (or strings), sequences, or arrays. But the power of RxJS is that it can deal with dynamic data sources in exactly the same way.

Components of an Rx Stream

Producer

A stream must always have a Producer - source of data. It is the starting point for any logic performing in RxJS.

In practice, a Producer is created from something that generates events independently (a single value, an array, mouse clicks, a bytes stream from a file). In RxJS, we call it Observable (as it’s able to be observed).

Observable is responsible for something like pushing notifications, which means that it only emits events and doesn’t care about consuming them.

Consumer

We also need a Consumer to accept events from the Producer and process them in some specific ways. When Consumer begins listening (subscribing) to Producer for events, we now have a Stream. RxJS uses Consumer as an Observer.

With RxJS, streams travel only from the Producer to the Consumer, not the other way around. This means that streams always flow from an Observable to an Observer. In addition, both components are loosely coupled:

Once the Observer begins receiving events from the Observable, what can we do with the data?

Within the Data Pipeline.

Data Pipeline

RxJS gives us ability to manipulate and edit data when it passes from Producer to Consumer by a list of methods (Observable operators). It means that we can adapt the output of the Producer to match the expectations of the Consumer.

More at:

https://grokonez.com/frontend/introduction-to-rxjs-javascript-reactive-stream

Introduction to RxJS – Extensions for JavaScript Reactive Streams

#rxjs #javascript #reactive #streams

What is GEEK

Buddha Community

Introduction to RxJS - Extensions for JavaScript Reactive Streams » grokonez

https://grokonez.com/frontend/introduction-to-rxjs-javascript-reactive-stream

Introduction to RxJS – Extensions for JavaScript Reactive Streams

Reactive Extensions for JavaScript (RxJS) is a precise alternative for callback or Promise-based libraries. It treats any ubiquitous source of events in the exact same manner, whether it is reading a file, making an HTTP call, clicking a button, or moving the mouse. RxJS is built on top of the pillars of functional and reactive programming, as well as a few popular design patterns such as Observer and Iterator.

Everything - just like a Stream

To work with RxJS, we should think in terms of streams. The image below shows a simple stream (or pipeline) approach to handling data:

• Producer is data source that produces various forms of data to be consumed.
• Pipeline is series of logic blocks that will be executed in order when data becomes available. The data (stream of asynchronous data) are filtered and processed in different ways so that they can be more easily consumed by Consumer.
• Consumer subscribes to (or listen for) Producer’s events and will do something with (consume) received data.

Any data point that holds one or more values, from a single integer to bytes of data, can be applied to the concept of a stream. Streams originate from a Producer, where data flows through a pipeline, arriving at a Consumer.

For example, we have set of operations (filter, map) that occurs between the creation of the Producer of the stream (the array) and the Consumer (the function that logs to the console):

We can create streams from static data sources: numbers (or strings), sequences, or arrays. But the power of RxJS is that it can deal with dynamic data sources in exactly the same way.

Components of an Rx Stream

Producer

A stream must always have a Producer - source of data. It is the starting point for any logic performing in RxJS.

In practice, a Producer is created from something that generates events independently (a single value, an array, mouse clicks, a bytes stream from a file). In RxJS, we call it Observable (as it’s able to be observed).

Observable is responsible for something like pushing notifications, which means that it only emits events and doesn’t care about consuming them.

Consumer

We also need a Consumer to accept events from the Producer and process them in some specific ways. When Consumer begins listening (subscribing) to Producer for events, we now have a Stream. RxJS uses Consumer as an Observer.

With RxJS, streams travel only from the Producer to the Consumer, not the other way around. This means that streams always flow from an Observable to an Observer. In addition, both components are loosely coupled:

Once the Observer begins receiving events from the Observable, what can we do with the data?

Within the Data Pipeline.

Data Pipeline

RxJS gives us ability to manipulate and edit data when it passes from Producer to Consumer by a list of methods (Observable operators). It means that we can adapt the output of the Producer to match the expectations of the Consumer.

More at:

https://grokonez.com/frontend/introduction-to-rxjs-javascript-reactive-stream

Introduction to RxJS – Extensions for JavaScript Reactive Streams

#rxjs #javascript #reactive #streams

Introduction With Basic JavaScript

The world’s most misunderstood programming language is JavaScript but JavaScript is now used by an incredible number of high-profile applications. So, it’s an important skill for any web or mobile developer to enrich the deeper knowledge in it.

Unlike most programming languages, the JavaScript language has no concept of input or output. It is designed to run as a scripting language in a host environment, and it is up to the host environment to provide mechanisms for communicating with the outside world.

Its syntax is based on the Java and C languages — many structures from those languages apply to JavaScript as well. JavaScript supports object-oriented programming with object prototypes, instead of classes. JavaScript also supports functional programming — because they are objects, functions may be stored in variables and passed around like any other object.

Let’s start off by looking at the building blocks of any language: the types. JavaScript programs manipulate values, and those values all belong to a type. JavaScript’s types are:

· Number

· String

· Boolean

· Function

· Object

· Symbol

and undefined and null, which are … slightly odd. And Array, which is a special kind of object. Date and RegExp, which are objects that you get for free. And to be technically accurate, functions are just a special type of object. So the type of diagram looks like this:

#beginner-javascript #javascript #javascript-introduction #javascript-fundamental #basic-javascritp

Reactive Streams in JavaScript with RSocket Flowable

When programming async operations, JavaScript developers are generally at least familiar with Promises, async/await, and callbacks. However, newer async models such as ReactiveX (RxJS in JavaScript), are not quite as popular. In this article, we dig into something similar but slightly different to RxJS; a Reactive Streams implementation called RSocket Flowable (rsocket-flowable on npm).

#rsocket #javascript #reactive-streams #reactive-programming #programming

Stateful stream processing with Apache Flink(part 1): An introduction

Apache Flink, a 4th generation Big Data processing framework provides robust **stateful stream processing capabilitie**s. So, in a few parts of the blogs, we will learn what is Stateful stream processing. And how we can use Flink to write a stateful streaming application.

What is stateful stream processing?

In general, stateful stream processing is an application design pattern for processing an unbounded stream of events. Stateful stream processing means a** “State”** is shared between events(stream entities). And therefore past events can influence the way the current events are processed.

Let’s try to understand it with a real-world scenario. Suppose we have a system that is responsible for generating a report. It comprising the total number of vehicles passed from a toll Plaza per hour/day. To achieve it, we will save the count of the vehicles passed from the toll plaza within one hour. That count will be used to accumulate it with the further next hour’s count to find the total number of vehicles passed from toll Plaza within 24 hours. Here we are saving or storing a count and it is nothing but the “State” of the application.

Might be it seems very simple, but in a distributed system it is very hard to achieve stateful stream processing. Stateful stream processing is much more difficult to scale up because we need different workers to share the state. Flink does provide ease of use, high efficiency, and high reliability for the**_ state management_** in a distributed environment.

#apache flink #big data and fast data #flink #streaming #streaming solutions ##apache flink #big data analytics #fast data analytics #flink streaming #stateful streaming #streaming analytics

What is JavaScript - Stackfindover - Blog

Who invented JavaScript, how it works, as we have given information about Programming language in our previous article ( What is PHP ), but today we will talk about what is JavaScript, why JavaScript is used The Answers to all such questions and much other information about JavaScript, you are going to get here today. Hope this information will work for you.

Who invented JavaScript?

JavaScript language was invented by Brendan Eich in 1995. JavaScript is inspired by Java Programming Language. The first name of JavaScript was Mocha which was named by Marc Andreessen, Marc Andreessen is the founder of Netscape and in the same year Mocha was renamed LiveScript, and later in December 1995, it was renamed JavaScript which is still in trend.

What is JavaScript?

JavaScript is a client-side scripting language used with HTML (Hypertext Markup Language). JavaScript is an Interpreted / Oriented language called JS in programming language JavaScript code can be run on any normal web browser. To run the code of JavaScript, we have to enable JavaScript of Web Browser. But some web browsers already have JavaScript enabled.

Today almost all websites are using it as web technology, mind is that there is maximum scope in JavaScript in the coming time, so if you want to become a programmer, then you can be very beneficial to learn JavaScript.

JavaScript Hello World Program

In JavaScript, ‘document.write‘ is used to represent a string on a browser.

<script type="text/javascript">
	document.write("Hello World!");
</script>

How to comment JavaScript code?

• For single line comment in JavaScript we have to use // (double slashes)
• For multiple line comments we have to use / * – – * /

<script type="text/javascript">

//single line comment

/* document.write("Hello"); */

</script>

Advantages and Disadvantages of JavaScript

#javascript #javascript code #javascript hello world #what is javascript #who invented javascript