Rx.js allows for asynchronous programming using Observables that provide a stream of multiple values over time. The document discusses how Observables can be created from events, combined using operators like map, filter, and flatMap, and subscribed to in order to handle the stream of values. A drag and drop example is provided that creates an Observable stream of mouse drag events by combining mouse down, mouse move, and mouse up event streams. This allows treating the sequence of mouse events as a collection that can be transformed before handling the drag behavior.
The document discusses Rx.js, a library for reactive programming using Observables. It begins by introducing Rx.js and some of its key benefits over other approaches to asynchronous programming like callbacks and Promises. It then provides examples of using Observables to represent asynchronous data streams and operations like DOM events. Key points made include that Observables allow for lazy execution, cancellation, composition of existing event streams, and treating asynchronous values as collections. The document concludes by demonstrating how Rx.js allows building a Morse code parser by modeling DOM events and signals as Observable streams.
This document summarizes the new features and goals of RxJS version 5, which aims to improve the modularity, performance, debugging, and extensibility of the RxJS library. Key changes include making RxJS fully modular, improving performance by reducing allocations and call stack sizes, enhancing debugging with simpler operator implementations, and allowing better extensibility through subclassing Observables and maintaining Subject bi-directionality. Simpler unit tests using marble diagrams are also highlighted.
RxJS is a library for composing asynchronous and event-based programs by using observable sequences. It provides operators that allow transforming, filtering, and combining streams of data from diverse sources. Key features include:
- Representing asynchronous data streams with Observables
- Providing LINQ-like operators for querying and transforming streams
- Using Schedulers to control concurrency and synchronize streams with other asynchronous operations like user interactions, server requests, etc.
RxJS - The Reactive extensions for JavaScriptViliam Elischer
RxJS is a library for composing asynchronous and event-based programs using observable sequences and functional style operators. It provides developers with Observables to represent asynchronous data streams, operators to query those streams, and Schedulers to parameterize concurrency. Some key operators include map to project values, filter to select values, reduce to aggregate values, and flatMap to flatten nested observables. RxJS supports both hot and cold observables, and is used for tasks like DOM event handling, API communication, and state management in applications.
1. Rxjs provides a better way of handling asynchronous code through observables which are streams of values over time. Observables allow for cancellable, retryable operations and easy composition of different asynchronous sources.
2. Common Rxjs operators like map, filter, and flatMap allow transforming and combining observable streams. Operators make observables quite powerful for tasks like async logic, event handling, and API requests.
3. In Angular, observables are used extensively for tasks like HTTP requests, routing, and component communication. Key aspects are using async pipes for subscriptions and unsubscribing during lifecycle hooks. Rxjs greatly simplifies many common asynchronous patterns in Angular applications.
The document discusses RxJS, a library for reactive programming using Observables that provide an API for asynchronous programming with observable streams. It provides code examples of using RxJS to handle events, AJAX requests, and animations as Observables. It also compares RxJS to Promises and native JavaScript event handling, and lists several frameworks that use RxJS like Angular and Redux.
Async Redux Actions With RxJS - React Rally 2016Ben Lesh
Redux-observable allows combining RxJS and Redux by introducing Epics. Epics are Observable streams that handle asynchronous logic in response to Redux actions. This avoids callback hell and enables features like cancellation. An Epic takes an action stream, performs asynchronous operations like AJAX calls using RxJS, and dispatches result actions. This keeps Redux synchronous while managing complex async flows in a declarative and reusable way.
Video and slides synchronized, mp3 and slide download available at URL http://bit.ly/2a2Djbp.
Gerard Sans explains RxJS' data architecture based on reactive programming, exploring Observables API using RxJS koans and unit tests. RxJS 5 focuses on performance and usability. Filmed at qconlondon.com.
Gerard Sans is a multi-talented Computer Science Engineer specialised in Web. He has lived and worked for all sorts of companies in Germany, Brazil, UK and Spain. He enjoys running AngularJS Labs London, mentoring AngularJS students, participating in the community, giving talks and writing technical articles at Medium.
The document discusses Rx.js, a library for reactive programming using Observables. It begins by introducing Rx.js and some of its key benefits over other approaches to asynchronous programming like callbacks and Promises. It then provides examples of using Observables to represent asynchronous data streams and operations like DOM events. Key points made include that Observables allow for lazy execution, cancellation, composition of existing event streams, and treating asynchronous values as collections. The document concludes by demonstrating how Rx.js allows building a Morse code parser by modeling DOM events and signals as Observable streams.
This document summarizes the new features and goals of RxJS version 5, which aims to improve the modularity, performance, debugging, and extensibility of the RxJS library. Key changes include making RxJS fully modular, improving performance by reducing allocations and call stack sizes, enhancing debugging with simpler operator implementations, and allowing better extensibility through subclassing Observables and maintaining Subject bi-directionality. Simpler unit tests using marble diagrams are also highlighted.
RxJS is a library for composing asynchronous and event-based programs by using observable sequences. It provides operators that allow transforming, filtering, and combining streams of data from diverse sources. Key features include:
- Representing asynchronous data streams with Observables
- Providing LINQ-like operators for querying and transforming streams
- Using Schedulers to control concurrency and synchronize streams with other asynchronous operations like user interactions, server requests, etc.
RxJS - The Reactive extensions for JavaScriptViliam Elischer
RxJS is a library for composing asynchronous and event-based programs using observable sequences and functional style operators. It provides developers with Observables to represent asynchronous data streams, operators to query those streams, and Schedulers to parameterize concurrency. Some key operators include map to project values, filter to select values, reduce to aggregate values, and flatMap to flatten nested observables. RxJS supports both hot and cold observables, and is used for tasks like DOM event handling, API communication, and state management in applications.
1. Rxjs provides a better way of handling asynchronous code through observables which are streams of values over time. Observables allow for cancellable, retryable operations and easy composition of different asynchronous sources.
2. Common Rxjs operators like map, filter, and flatMap allow transforming and combining observable streams. Operators make observables quite powerful for tasks like async logic, event handling, and API requests.
3. In Angular, observables are used extensively for tasks like HTTP requests, routing, and component communication. Key aspects are using async pipes for subscriptions and unsubscribing during lifecycle hooks. Rxjs greatly simplifies many common asynchronous patterns in Angular applications.
The document discusses RxJS, a library for reactive programming using Observables that provide an API for asynchronous programming with observable streams. It provides code examples of using RxJS to handle events, AJAX requests, and animations as Observables. It also compares RxJS to Promises and native JavaScript event handling, and lists several frameworks that use RxJS like Angular and Redux.
Async Redux Actions With RxJS - React Rally 2016Ben Lesh
Redux-observable allows combining RxJS and Redux by introducing Epics. Epics are Observable streams that handle asynchronous logic in response to Redux actions. This avoids callback hell and enables features like cancellation. An Epic takes an action stream, performs asynchronous operations like AJAX calls using RxJS, and dispatches result actions. This keeps Redux synchronous while managing complex async flows in a declarative and reusable way.
Video and slides synchronized, mp3 and slide download available at URL http://bit.ly/2a2Djbp.
Gerard Sans explains RxJS' data architecture based on reactive programming, exploring Observables API using RxJS koans and unit tests. RxJS 5 focuses on performance and usability. Filmed at qconlondon.com.
Gerard Sans is a multi-talented Computer Science Engineer specialised in Web. He has lived and worked for all sorts of companies in Germany, Brazil, UK and Spain. He enjoys running AngularJS Labs London, mentoring AngularJS students, participating in the community, giving talks and writing technical articles at Medium.
This document discusses RxJS marble testing. It provides an overview of Observables, Schedulers, and the TestScheduler. The TestScheduler allows testing asynchronous code by virtualizing time, mocking Observables with marble diagrams, and asserting expected emissions. Examples demonstrate creating cold Observables, time, and testing an Epic that uses delay with the redux-observable-test-helper. Marble testing makes asynchronous code more testable.
The document discusses how to use RxJS (Reactive Extensions library for JavaScript) to treat events like arrays by leveraging Observable types and operators. It explains key differences between Observables and Promises/Arrays, how Observables are lazy and cancelable unlike Promises. Various RxJS operators like map, filter, interval and fromEvent are demonstrated for transforming and composing Observable streams. The document aims to illustrate how RxJS enables treating events as collections that can be processed asynchronously over time.
서버 개발자가 바라 본 Functional Reactive Programming with RxJava - SpringCamp2015NAVER / MusicPlatform
youtube : https://youtu.be/E_Bgv9upahI
비동기 이벤트 기반의 라이브러리로만 생각 했던 RxJava가 지금 이 시대 프로그래머에게 닥쳐 올 커다란 메시지라는 사실을 알게 된 지금. 현장에서 직접 느낀 RxJava의 본질인 Function Reactive Programming(FRP)에 대해 우리가 잘 아는 Java 이야기로 풀어 보고 ReactiveX(RxJava) 개발을 위한 서버 환경에 대한 이해와 SpringFramework, Netty에서의 RxJava를 어떻게 이용 하고 개발 했는지 공유 하고자 합니다.
The document contains 6 programming tasks involving object-oriented concepts like classes, operators overloading, constructors etc. in C++. The tasks include modifying existing classes to add new functionality like operator overloading for arithmetic, relational and logical operators. New classes are also designed from scratch implementing various features like constructors, member functions and operator overloading. Main functions are written to test the classes.
This document provides an overview of various JavaScript concepts and techniques, including:
- Prototypal inheritance allows objects in JavaScript to inherit properties from other objects. Functions can act as objects and have a prototype property for inheritance.
- Asynchronous code execution in JavaScript is event-driven. Callbacks are assigned as event handlers to execute code when an event occurs.
- Scope and closures - variables are scoped to functions. Functions create closures where they have access to variables declared in their parent functions.
- Optimization techniques like event delegation and requestAnimationFrame can improve performance of event handlers and animations.
Shift Remote FRONTEND: Reactivity in Vue.JS 3 - Marko Boskovic (Barrage)Shift Conference
In previous versions of Vue we needed abstracted patterns like Higher Order Components (HOC), mixins or props to implement reactivity. The new functional API gives us the ability to encapsulate and reuse logic across multiple components without those abstracted patterns.
RxJS Operators - Real World Use Cases (FULL VERSION)Tracy Lee
This document provides an overview and explanation of various RxJS operators for working with Observables, including:
- The map, filter, and scan operators for transforming streams of data. Map applies a function to each value, filter filters values, and scan applies a reducer function over time.
- Flattening operators like switchMap, concatMap, mergeMap, and exhaustMap for mapping Observables to other Observables.
- Error handling operators like catchError, retry, and retryWhen for catching and handling errors.
- Additional explanation of use cases and common mistakes for each operator discussed. The document is intended to explain these essential operators for real world reactive programming use.
RxJS101 - What you need to know to get started with RxJS tomorrowViliam Elischer
This document provides an overview of RxJS, a library for composing asynchronous and event-based programs using observable sequences. It discusses key RxJS concepts like Observables, Observers, Operators, and how to create and use Observables. It also provides learning resources and highlights improvements in RxJS 5 like compliance with the Observable specification and better performance.
The document discusses the benefits of using RxJS observables over promises and events for managing asynchronous and reactive code in Angular applications. It explains key concepts like observers, subscriptions, operators, cold vs hot observables, and using RxJS with services and components. Example code is provided for creating observable data services to share data between components, composing asynchronous logic with operators, and best practices for managing subscriptions and preventing memory leaks. Overall, the document promotes a reactive programming style with RxJS for building maintainable and testable Angular applications.
Concurrent applications with free monads and stmAlexander Granin
The document discusses using Free monads and STM (Software Transactional Memory) for building concurrent applications in Haskell. It provides examples of applications like a labyrinth game and meteor shower simulation that are built using Free monads, STM transactions, processes and signals to coordinate concurrent operations. The document also discusses building a blockchain application using a similar approach with nodes, services, state and declarative protocols.
Add Some Fun to Your Functional Programming With RXJSRyan Anklam
This document discusses using RxJS (Reactive Extensions for JavaScript) to add interactivity and animation to an autocomplete search widget. Key events are turned into observables and used to make AJAX requests and trigger animations. Observables are merged, concatenated, and flattened to coordinate the asynchronous events and animations over time. Functional programming concepts like map, filter, and reduce are used to transform and combine the observable streams.
Solid principles in practice the clean architecture - Droidcon ItalyFabio Collini
The Clean Architecture has been formalized by Robert C. Martin in 2012, it's quite new even if it's based on the SOLID principles (presented for the first time in early 2000). The biggest benefit that we get using this architecture is the code testability, indeed it separates the application code from the code connected to external factor (that usually is more difficult to test).
In this talk we'll see a practical example of how to apply the SOLID principle, in particular, the dependency inversion.
SOLID principles in practice: the Clean ArchitectureFabio Collini
The Clean Architecture has been formalized by Robert C. Martin in 2012, it's quite new even if it's based on the SOLID principles (presented for the first time in early 2000). The biggest benefit that we get using this architecture is the code testability, indeed it separates the application code from the code connected to external factor (that usually is more difficult to test).
In this talk we'll see a practical example of how to apply the SOLID principle, in particular, the dependency inversion.
Тема №2 Расширяем сознание реактивным подходом. RxJava и Android
Спикер — Владимир Артеменко — android developer Компания Rooky Pro
Уровень аудитории — Теория есть, начальный опыт применения
Цель доклада – Обучение
Think Async: Asynchronous Patterns in NodeJSAdam L Barrett
JavaScript is single threaded, so understanding the async patterns available in the language is critical to creating maintainable NodeJS applications with good performance. In order to master “thinking in async”, we’ll explore the async patterns available in node and JavaScript including standard callbacks, promises, thunks/tasks, the new async/await, the upcoming asynchronous iteration features, streams, CSP and ES Observables.
The document discusses virtual machines and JavaScript engines. It provides a brief history of virtual machines from the 1970s to today. It then explains how virtual machines work, including the key components of a parser, intermediate representation, interpreter, garbage collection, and optimization techniques. It discusses different approaches to interpretation like switch statements, direct threading, and inline threading. It also covers compiler optimizations and just-in-time compilation that further improve performance.
This document provides an overview of key concepts for working with D3, including:
- D3 uses standard web technologies like HTML, SVG, and CSS rather than introducing new representations. Learning D3 largely means learning web standards.
- Visualization with D3 requires mapping data to visual elements using scales. Scales are functions that map from data values to visual values like pixel positions.
- Selections in D3 correspond to elements in the DOM. Data joins allow binding data to selections to drive attribute updates. The enter, update, exit pattern is used to handle new, existing and removed data.
- Common scale types include linear, log, quantize and quantile for quantitative data, and
Lightning Talk on Software Transactional Memory in Scala. The Actors Pattern has gotten a lot of attention in the Scala ecosphere, but STM of often a good first solution for solving concurrency problems. It's odd that it hasn't had as much attention in the Scala world, so this talk aims to show how easy it is to use, and compare it to typical lock-based synchronization by showing how easy it is to make errors with lock-based synchronization
The document introduces Elm, a functional programming language that compiles to JavaScript. It has a focus on simplicity, robustness, and helping developers avoid bugs. Some key points about Elm include its functional, immutable, and statically typed nature; built-in support for functional reactive programming; use for building rich user interfaces; and emphasis on easy refactoring and adding new features. The document also discusses Elm's syntax, type system, record handling, approach to avoiding runtime exceptions, architecture for user interface apps, and ecosystem of tools.
This document discusses RxJS marble testing. It provides an overview of Observables, Schedulers, and the TestScheduler. The TestScheduler allows testing asynchronous code by virtualizing time, mocking Observables with marble diagrams, and asserting expected emissions. Examples demonstrate creating cold Observables, time, and testing an Epic that uses delay with the redux-observable-test-helper. Marble testing makes asynchronous code more testable.
The document discusses how to use RxJS (Reactive Extensions library for JavaScript) to treat events like arrays by leveraging Observable types and operators. It explains key differences between Observables and Promises/Arrays, how Observables are lazy and cancelable unlike Promises. Various RxJS operators like map, filter, interval and fromEvent are demonstrated for transforming and composing Observable streams. The document aims to illustrate how RxJS enables treating events as collections that can be processed asynchronously over time.
서버 개발자가 바라 본 Functional Reactive Programming with RxJava - SpringCamp2015NAVER / MusicPlatform
youtube : https://youtu.be/E_Bgv9upahI
비동기 이벤트 기반의 라이브러리로만 생각 했던 RxJava가 지금 이 시대 프로그래머에게 닥쳐 올 커다란 메시지라는 사실을 알게 된 지금. 현장에서 직접 느낀 RxJava의 본질인 Function Reactive Programming(FRP)에 대해 우리가 잘 아는 Java 이야기로 풀어 보고 ReactiveX(RxJava) 개발을 위한 서버 환경에 대한 이해와 SpringFramework, Netty에서의 RxJava를 어떻게 이용 하고 개발 했는지 공유 하고자 합니다.
The document contains 6 programming tasks involving object-oriented concepts like classes, operators overloading, constructors etc. in C++. The tasks include modifying existing classes to add new functionality like operator overloading for arithmetic, relational and logical operators. New classes are also designed from scratch implementing various features like constructors, member functions and operator overloading. Main functions are written to test the classes.
This document provides an overview of various JavaScript concepts and techniques, including:
- Prototypal inheritance allows objects in JavaScript to inherit properties from other objects. Functions can act as objects and have a prototype property for inheritance.
- Asynchronous code execution in JavaScript is event-driven. Callbacks are assigned as event handlers to execute code when an event occurs.
- Scope and closures - variables are scoped to functions. Functions create closures where they have access to variables declared in their parent functions.
- Optimization techniques like event delegation and requestAnimationFrame can improve performance of event handlers and animations.
Shift Remote FRONTEND: Reactivity in Vue.JS 3 - Marko Boskovic (Barrage)Shift Conference
In previous versions of Vue we needed abstracted patterns like Higher Order Components (HOC), mixins or props to implement reactivity. The new functional API gives us the ability to encapsulate and reuse logic across multiple components without those abstracted patterns.
RxJS Operators - Real World Use Cases (FULL VERSION)Tracy Lee
This document provides an overview and explanation of various RxJS operators for working with Observables, including:
- The map, filter, and scan operators for transforming streams of data. Map applies a function to each value, filter filters values, and scan applies a reducer function over time.
- Flattening operators like switchMap, concatMap, mergeMap, and exhaustMap for mapping Observables to other Observables.
- Error handling operators like catchError, retry, and retryWhen for catching and handling errors.
- Additional explanation of use cases and common mistakes for each operator discussed. The document is intended to explain these essential operators for real world reactive programming use.
RxJS101 - What you need to know to get started with RxJS tomorrowViliam Elischer
This document provides an overview of RxJS, a library for composing asynchronous and event-based programs using observable sequences. It discusses key RxJS concepts like Observables, Observers, Operators, and how to create and use Observables. It also provides learning resources and highlights improvements in RxJS 5 like compliance with the Observable specification and better performance.
The document discusses the benefits of using RxJS observables over promises and events for managing asynchronous and reactive code in Angular applications. It explains key concepts like observers, subscriptions, operators, cold vs hot observables, and using RxJS with services and components. Example code is provided for creating observable data services to share data between components, composing asynchronous logic with operators, and best practices for managing subscriptions and preventing memory leaks. Overall, the document promotes a reactive programming style with RxJS for building maintainable and testable Angular applications.
Concurrent applications with free monads and stmAlexander Granin
The document discusses using Free monads and STM (Software Transactional Memory) for building concurrent applications in Haskell. It provides examples of applications like a labyrinth game and meteor shower simulation that are built using Free monads, STM transactions, processes and signals to coordinate concurrent operations. The document also discusses building a blockchain application using a similar approach with nodes, services, state and declarative protocols.
Add Some Fun to Your Functional Programming With RXJSRyan Anklam
This document discusses using RxJS (Reactive Extensions for JavaScript) to add interactivity and animation to an autocomplete search widget. Key events are turned into observables and used to make AJAX requests and trigger animations. Observables are merged, concatenated, and flattened to coordinate the asynchronous events and animations over time. Functional programming concepts like map, filter, and reduce are used to transform and combine the observable streams.
Solid principles in practice the clean architecture - Droidcon ItalyFabio Collini
The Clean Architecture has been formalized by Robert C. Martin in 2012, it's quite new even if it's based on the SOLID principles (presented for the first time in early 2000). The biggest benefit that we get using this architecture is the code testability, indeed it separates the application code from the code connected to external factor (that usually is more difficult to test).
In this talk we'll see a practical example of how to apply the SOLID principle, in particular, the dependency inversion.
SOLID principles in practice: the Clean ArchitectureFabio Collini
The Clean Architecture has been formalized by Robert C. Martin in 2012, it's quite new even if it's based on the SOLID principles (presented for the first time in early 2000). The biggest benefit that we get using this architecture is the code testability, indeed it separates the application code from the code connected to external factor (that usually is more difficult to test).
In this talk we'll see a practical example of how to apply the SOLID principle, in particular, the dependency inversion.
Тема №2 Расширяем сознание реактивным подходом. RxJava и Android
Спикер — Владимир Артеменко — android developer Компания Rooky Pro
Уровень аудитории — Теория есть, начальный опыт применения
Цель доклада – Обучение
Think Async: Asynchronous Patterns in NodeJSAdam L Barrett
JavaScript is single threaded, so understanding the async patterns available in the language is critical to creating maintainable NodeJS applications with good performance. In order to master “thinking in async”, we’ll explore the async patterns available in node and JavaScript including standard callbacks, promises, thunks/tasks, the new async/await, the upcoming asynchronous iteration features, streams, CSP and ES Observables.
The document discusses virtual machines and JavaScript engines. It provides a brief history of virtual machines from the 1970s to today. It then explains how virtual machines work, including the key components of a parser, intermediate representation, interpreter, garbage collection, and optimization techniques. It discusses different approaches to interpretation like switch statements, direct threading, and inline threading. It also covers compiler optimizations and just-in-time compilation that further improve performance.
This document provides an overview of key concepts for working with D3, including:
- D3 uses standard web technologies like HTML, SVG, and CSS rather than introducing new representations. Learning D3 largely means learning web standards.
- Visualization with D3 requires mapping data to visual elements using scales. Scales are functions that map from data values to visual values like pixel positions.
- Selections in D3 correspond to elements in the DOM. Data joins allow binding data to selections to drive attribute updates. The enter, update, exit pattern is used to handle new, existing and removed data.
- Common scale types include linear, log, quantize and quantile for quantitative data, and
Lightning Talk on Software Transactional Memory in Scala. The Actors Pattern has gotten a lot of attention in the Scala ecosphere, but STM of often a good first solution for solving concurrency problems. It's odd that it hasn't had as much attention in the Scala world, so this talk aims to show how easy it is to use, and compare it to typical lock-based synchronization by showing how easy it is to make errors with lock-based synchronization
The document introduces Elm, a functional programming language that compiles to JavaScript. It has a focus on simplicity, robustness, and helping developers avoid bugs. Some key points about Elm include its functional, immutable, and statically typed nature; built-in support for functional reactive programming; use for building rich user interfaces; and emphasis on easy refactoring and adding new features. The document also discusses Elm's syntax, type system, record handling, approach to avoiding runtime exceptions, architecture for user interface apps, and ecosystem of tools.
— Табуретка Нормана и как на ней усидеть в огромной продуктовой компании UX команде
— «Хочу» не равно «Нада»: валидация гипотез и интерпритация данных
— Проектирование для B2B / B2C / C2C / B2G
— Симбиоз нескольких методологий проектирования
Modern javascript localization with c-3po and the good old gettextAlexander Mostovenko
This document summarizes a presentation about localization in modern JavaScript applications using GNU gettext. Some key points:
- GNU gettext is recommended over ICU due to better tooling and compatibility with existing backend formats.
- C-3po is an open source library that improves on gettext by allowing extraction and resolution of translations directly from JavaScript code using tagged template literals.
- It implements an extraction/merge/resolve workflow that allows developers and translators to work independently and precompiles translations for faster loading.
The SlideShare 101 is a quick start guide if you want to walk through the main features that the platform offers. This will keep getting updated as new features are launched.
The SlideShare 101 replaces the earlier "SlideShare Quick Tour".
WebCamp:Front-end Developers Day. Александр Мостовенко "Rx.js - делаем асинхр...GeeksLab Odessa
04.07.2015 WebCamp:Front-end Developers Day
Александр Мостовенко (Python developer at Prom.ua)
"Rx.js - делаем асинхронное программирование проще"
В данном докладе будет рассмотрено преимущество FRP подхода к построению javascript приложений на примере библиотеки Rx.js. Узнаем как Rx.js позволяет избавиться от callback hell и превращает сложные вещи в простые.
Подробнее:
http://geekslab.co,
http://webcamp.in.ua/
https://www.facebook.com/GeeksLab.co , https://www.facebook.com/OdessaInnovationWeek
https://www.youtube.com/user/GeeksLabVideo
Rxjs provides a paradigm for dealing with asynchronous operations in a way that resembles synchronous code. It uses Observables to represent asynchronous data streams over time that can be composed using operators. This allows handling of events, asynchronous code, and other reactive sources in a declarative way. Key points are:
- Observables represent asynchronous data streams that can be subscribed to.
- Operators allow manipulating and transforming streams through methods like map, filter, switchMap.
- Schedulers allow controlling virtual time for testing asynchronous behavior.
- Promises represent single values while Observables represent continuous streams, making Observables more powerful for reactive programming.
- Cascading asynchronous calls can be modeled elegantly using switch
1) Rxjs provides a paradigm for dealing with asynchronous operations in a synchronous way using observables. Observables allow representing push-based data streams and provide operators to compose and transform these streams.
2) Operators like map, filter, and switchMap allow manipulating observable streams and their values in various ways. Common patterns include cascading asynchronous calls, parallelizing multiple requests, and retrying or error handling of streams.
3) Schedulers allow bending time and virtual clocks, enabling testing asynchronous code by controlling when asynchronous operations complete. Marble testing uses descriptive patterns to visually test observable streams and operator behavior.
This document provides an overview of Rxjs (Reactive Extensions for JavaScript). It begins by explaining why Rxjs is useful for dealing with asynchronous code in a synchronous way and provides one paradigm for asynchronous operations. It then discusses the history of callbacks and promises for asynchronous code. The bulk of the document explains key concepts in Rxjs including Observables, Operators, error handling, testing with Schedulers, and compares Promises to Rxjs. It provides examples of many common Rxjs operators and patterns.
The document provides an introduction to RxJS (Reactive Extensions for JavaScript), which is a reactive programming library for asynchronous operations. It discusses key RxJS concepts like Observables, operators, and functional reactive programming. It also provides examples of using RxJS to handle events asynchronously and processing streams of data.
The document discusses reactive programming and frameworks. It introduces reactive programming as a way to think about asynchronous and event-based programming that is fundamental to cloud, web and mobile applications. It shows how asynchronous and event-based computations can be viewed as push-based collections by dualizing enumerable collections to observable collections. This allows applying LINQ-style queries to asynchronous programming. Examples are provided for moving a ball with keyboard input and dragging the mouse to draw, implemented imperatively and declaratively with observables.
The document discusses reactive programming and reactive systems. It defines the three parts of the reactive spectrum as reactive (software showing responses to stimuli), reactive systems (frameworks like Akka and Vert.x), and reactive programming (programming models using streams/flows like RxJava). It discusses key aspects of reactive systems like asynchronous programming, back pressure in streams to handle varying workloads, and using reactive types like Singles, Maybes and Completables. The document advocates for building responsive distributed systems using these reactive principles and introduces Vert.x as a toolkit for building such systems.
This document provides an overview of ReactiveX (Rx), which is an API for asynchronous programming using observable streams. It discusses key Rx concepts like Observables, which represent sets of values over time that can be subscribed to; Operators, which allow transforming, combining, and manipulating observable streams; and Subjects, which act as both Observable and Observer and are useful for multicasting streams. The document provides examples of using Rx in autocomplete applications and discusses Schedulers, which define the execution context for asynchronous operations in Rx. Overall, the document serves as a high-level introduction to the reactive programming paradigm and Rx library.
Funtional Reactive Programming with Examples in Scala + GWTVasil Remeniuk
This document provides an overview of functional reactive programming (FRP) with examples using Scala and GWT (Google Web Toolkit). It discusses how FRP can be used to build user interfaces that synchronize state changes automatically in response to events. Key concepts explained include EventStreams, Signals, and how they can be transformed and combined. Examples show how FRP can be used to track mouse position, build stock tickers that update dynamically, and manage collections of values that change over time. The document argues that FRP provides advantages over the traditional observer pattern for building interactive user interfaces.
Asynchronous web apps with the Play Framework 2.0Oscar Renalias
This document discusses Play's asynchronous capabilities for building scalable and responsive web applications. It begins by explaining the traditional blocking request processing model and Play's asynchronous non-blocking model. It then covers asynchronous requests using Futures and Promises in Play. Examples are provided for making actions asynchronous using asynchronous responses. The document also discusses reactive IO in Play using Enumerators and Iteratees for non-blocking streaming of data. Real world use cases for asynchronous programming include asynchronous web services, streaming files and data, and websockets.
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2. About me
Mostovenko Alexander
Python developer at
Writing mostly in python and coffeescript.
Love FP stuff.
Traveling, snowboarding, cycling.
https://twitter.com/MostovenkoA
https://github.com/AlexMost
3. Why Rx.js and not another FRP lib?
● Implemented in a lot of languages
(.NET, Java, Ruby, Python, Clojure, Scala,
Haskell, Objective-C).
● Has a huge amount of docs and examples.
● Why not?
29. Callback vs Black hole
some_async_func(function(err, result) {
// ... looks like we are in trap
another_wonderful_func(function(err, result){
// ... you are in trap
});
});
35. Why we should look at Observable?
1. Promise represents only single value.
2. How to cancel?
3. Lazy execution.
4. We can work with Observable as easy as with
promise.
38. Observable
var source = Rx.Observable.create((observer) =>
// some async operation
observer.onNext(data)
// or ..
observer.onError(data)
// or ..
observer.onCompleted(data)
);
source.subscribe(
(data) => {}
(err) => {}
)
39. Observlable vs promise example
var source = Rx.Observable.create((observer) => {
setTimeout(() => {
console.log("observable timeout hit");
observer.onNext(25);
}, 500);
console.log('observable started')});
source.subscribe(x => console.log(`observable value ${x}`));
Observable
> observable started
> observable timeout hit
> observable value 25
40. Observlable vs promise example
var promise = new Promise((resolve) => {
setTimeout(() => {
console.log("promise timeout hit");
resolve(25);
}, 500);
console.log("promise started");});
promise.then(x => console.log(`promise value ${x}`));
Promise
> promise started
> promise timeout hit
> promise value 25
44. Asynchronous programming landscape
multiple
values
single
value
sync async
a = f(x) a = f(x).then(...)
collection = [1, 2, 3]
a = collection
.filter((v) => v > 2)
move = Rx.Observable.fromEvent(document, 'mousemove')
my_moves = move
.filter((ev) => ev.clientX > 100)
my_moves.subscribe(...)
Promise
Array
value
Observable
45. How to create Observable
● Observable.create
● Observable.fromEvent
● Observable.fromNodeCallback
● Observable.fromArray
● Observable.fromPromise
46. Drag & Drop example
What if i told you ….
That mouse move event is an array and you
can map, filter over it?
47. var dragTarget = document.getElementById('dragTarget');
// Get the three major events collections
var mouseup = Rx.DOM.fromEvent(dragTarget, 'mouseup');
var mousemove = Rx.DOM.fromEvent(document, 'mousemove');
var mousedown = Rx.DOM.fromEvent(dragTarget, 'mousedown');
var mousedrag = mousedown.flatMap(({offsetX, offsetY}) => {
return mousemove
.map(({clientX: x, clientY: y}) => {
return {left: x - offsetX, top: y - offsetY}})
.takeUntil(mouseup)
});
var subscription = mousedrag.subscribe((pos) => {
dragTarget.style.top = pos.top + 'px';
dragTarget.style.left = pos.left + 'px';
});
48. var dragTarget = document.getElementById('dragTarget');
// Get the three major events collections
var mouseup = Rx.DOM.fromEvent(dragTarget, 'mouseup');
var mousemove = Rx.DOM.fromEvent(document, 'mousemove');
var mousedown = Rx.DOM.fromEvent(dragTarget, 'mousedown');
var mousedrag = mousedown.flatMap(({offsetX, offsetY}) => {
return mousemove
.map(({clientX: x, clientY: y}) => {
return {left: x - offsetX, top: y - offsetY}})
.takeUntil(mouseup)
});
var subscription = mousedrag.subscribe((pos) => {
dragTarget.style.top = pos.top + 'px';
dragTarget.style.left = pos.left + 'px';
});
Create observable collections
from DOM events
49. var dragTarget = document.getElementById('dragTarget');
// Get the three major events collections
var mouseup = Rx.DOM.fromEvent(dragTarget, 'mouseup');
var mousemove = Rx.DOM.fromEvent(document, 'mousemove');
var mousedown = Rx.DOM.fromEvent(dragTarget, 'mousedown');
var mousedrag = mousedown.flatMap(({offsetX, offsetY}) => {
return mousemove
.map(({clientX: x, clientY: y}) => {
return {left: x - offsetX, top: y - offsetY}})
.takeUntil(mouseup)
});
var subscription = mousedrag.subscribe((pos) => {
dragTarget.style.top = pos.top + 'px';
dragTarget.style.left = pos.left + 'px';
});
Using power of Rx, combine
existing event streams to produce
mouse drag event collection
50. var dragTarget = document.getElementById('dragTarget');
// Get the three major events collections
var mouseup = Rx.DOM.fromEvent(dragTarget, 'mouseup');
var mousemove = Rx.DOM.fromEvent(document, 'mousemove');
var mousedown = Rx.DOM.fromEvent(dragTarget, 'mousedown');
var mousedrag = mousedown.flatMap(({offsetX, offsetY}) => {
return mousemove
.map(({clientX: x, clientY: y}) => {
return {left: x - offsetX, top: y - offsetY}})
.takeUntil(mouseup)
});
var subscription = mousedrag.subscribe((pos) => {
dragTarget.style.top = pos.top + 'px';
dragTarget.style.left = pos.left + 'px';
});
Subscribe on mouse drag events,
updating top and left attributes
51. Observable are first class events
Can be:
- passed as a parameter
- returned from a function
- assigned to a variable
52.
53. Some common basic operations
map
filter
reduce
zip
merge
flatMap
...
https://github.com/Reactive-Extensions/RxJS/blob/master/doc/api/core/observable.md
80. dispatchActions = (view, eventStream, store) ->
incrementClickStream = eventStream
.filter(({action}) -> action is "increment_click_count")
.do(-> store.incrementClicksCount())
Rx.Observable.merge(
incrementClickStream
# some more actions here for updating view ...
).subscribe(
-> view.setProps getViewState(store)
(err) ->
console.error? err)
RxReact (simple click count)
81. dispatchActions = (view, eventStream, store) ->
incrementClickStream = eventStream
.filter(({action}) -> action is "increment_click_count")
.do(-> store.incrementClicksCount())
Rx.Observable.merge(
incrementClickStream
# some more actions here for updating view ...
).subscribe(
-> view.setProps getViewState(store)
(err) ->
console.error? err)
RxReact (simple click count)
stream from view for increment and storage
modification
82. dispatchActions = (view, eventStream, store) ->
incrementClickStream = eventStream
.filter(({action}) -> action is "increment_click_count")
.do(-> store.incrementClicksCount())
Rx.Observable.merge(
incrementClickStream
# some more actions here for updating view ...
).subscribe(
-> view.setProps getViewState(store)
(err) ->
console.error? err)
RxReact (simple click count)
merge all streams that can modify UI
83. dispatchActions = (view, eventStream, store) ->
incrementClickStream = eventStream
.filter(({action}) -> action is "increment_click_count")
.do(-> store.incrementClicksCount())
Rx.Observable.merge(
incrementClickStream
# some more actions here for updating view ...
).subscribe(
-> view.setProps getViewState(store)
(err) ->
console.error? err)
RxReact (simple click count)
update UI, making setProps on view
component
84. RxReact (simple click count)
More complex case
1. Decrement.
2. Sync with server (per 1 second).
3. Sync only if value changed.
4. Show sync success message.
5. Hide success message after 2 seconds.
demo - http://alexmost.github.io/RxReact/hello_world2/public/index.html
code - https://github.com/AlexMost/RxReact/tree/master/hello_world2/hello_world2
90. Conclusion
● Rx is a powerful tool for writing async code
● Helps to write modular and composable code
● Solves a lot of hard testing problems
● Solves problem of error handling and resource
management