Real-Time stream processing with Reactive-Extensions (RX)

A playful example of using RX to create a morse code generator with RxJs and Angular (No Angular knowledge needed!)

Agenda:

• The ancient story of RxJs
• Marble-Diagrams
• Explaining the goal
• Overview over the code base we begin with
• Live coding
  • Use a button to create a stream of timestamps
  • Transform timestamps to dots (".") and dashes ("_")
  • Translate series of dost and dashes to readable text
  • Handling edge cases
  • Handling errors
• Resources
• Good bye!

Demo

Find the final code online at angular-morse-code-example

Overview

Using RxJs to process streams in real-time. In this talk you will get an overview of Reactive-Extensions and see it's usage in a live-coding session.

First you will get an introduction into Rx and it's history. After covering the basic concepts and terminologies we will get better understanding of observables and learn how to use marble-diagrams for documentation.

In the live-coding session I create a morse-code generator to demonstrate real-time stream processing in a playful way. You will get basic knowledge in mosing and alot more over RX.

I will show you:

• how to create observables
• common operators to transform streams
• different ways to combine streams
• subscription handling
• error handling
• exposing observables
• how to use subjects to control streams

After the session you will have enough knowledge to start using Rx in any language not only in javascript.

Intro to RxJs

RxJs in 2 sentences, inventor, story of the idea, technical explanation,

How i am/What i do

name, interests, background of the example, what my bussines is

Marble-Diagrams

buildingg blocks aof marble diagrams, examples, show rxmarbles

Explaining the goal

Generate timestamps for start and end of sending a signal Calculate duration of moude down and up Transform to character Transform to symbol Transform to letter

Overview over the code base we begin with

buttom and display functionality, connection of service to components

Live coding

In the livecoding session we will create following code in the service class which basically contains all Rx logic

And this code for the visualisation in the component

Use a button to create a stream of timestamps

Subjects, exposing, usage of display

Transform timestamps to dots (".") and dashes ("_")

combineLatest, map and filter operator

Translate series of dost and dashes to readable text

window, flatmap, map and filer operator

Handling errors

filter, switchMap and catch operator

Handling edge cases

.switchMap, timer and take operator

Resources

Good bye!

Things todo:

• find good example for hot and cold related to morse stuff
• create canvas component to draw strokes related to morse signals