Dealing with streams using RxJs

Transcript

1. Dealing with Streams using RxJS
2. Hello! I am Hugo Cordier Developer and CTO at Melusyn Melusyn helps film makers to manage and organize their productions. You can find me at : @HugoCrd We are hiring! Drop me a line at hugo@melusyn.com ♥
3. 1. What’s an event? Javascript is about events
4. What’s an event? DOM events clicks, moves, focuses, drags events
5. What’s an event? Async response Ajax, Websocket events
6. What’s an event? Timeout, interval Time related events
7. What’s an event? Solution Callbacks & Promises
8. 2. What’s a stream? Give me use-cases!
9. What’s a stream? A stream is a group of events
10. What’s a stream? Double clicks How fast can you click?
11. What’s a stream? Keyboard Konami code is a must have feature
12. What’s a stream? Synchronizing async responses Requesting several services
13. What’s a stream? Solution Reactive Extensions
14. 3. What to do with it?
15. What to do with it? Transforming events in the Stream
16. What to do with it? Merging, mixing Several streams
17. What to do with it? Dealing with time Delaying events, creating interval, ...
18. 4. The Rx Model Observables and Operators
19. The Rx Model A stream is an Observable An Observable push down events through Operators
20. The Rx Model Operators transform a stream They can be used to transform, filter and mix events from an Observable
21. The Rx Model
22. The Rx Model
23. The Rx Model myObservable .map(value => value+1) .filter(value => value > 2) Finally some code!
24. The Rx Model
25. The Rx Model myObservable .merge(anotherObservable) .map(value => value+1) .filter(value => value > 2)
26. The Rx Model
27. The Rx Model myObservable .flatMap(anotherObservable) .map(value => value+1)//Values from anotherObservable .filter(value => value > 2)
28. There’s a whole bunch of Operators The Rx Model http://reactivex.io/documentation/operators.html
29. 5. The Rx Model Subscribing and dealing with errors
30. An Observable needs to be subscribed The Rx Model The stream will flow once it has been subscribed
31. The Rx Model myObservable .subscribe( value => console.log(“Event”+value), e => console.error(e) )
32. 6. The Rx Model Creating Observables
33. How to create an Observable? The Rx Model
34. The Rx Model Rx.Observable .just(1) .from([1,5,0,12,4]) .fromEvent(domElement, event) .fromNodeCallback(nodeFct) .fromPromise(promise) .interval(2000)
35. The Rx Model Rx.Observable.create(s => { for (value in values) { s.onNext(value) } s.onCompleted() })
36. 7. In real life
37. In real life Live search Using Google Geocoder and RxJS http://codepen.io/HugoCrd/pen/vOxQvM
38. In real life Composing streams Aggregate data from several requests http://codepen.io/HugoCrd/pen/azGxdW
39. In real life Realtime statistics Ping a server each x seconds and diplay results http://codepen.io/HugoCrd/pen/dPeaLY
40. 8. In real life RxJS is just a library. Use it with whatever you want
41. In real life with... Node.js Node uses Callbacks. They can easily be used as a stream var rename = Rx.Observable.fromNodeCallback(fs.rename); rename('file1.txt', 'file2.txt') .map(...) .subscribe(...)
42. In real life with... Angular.js Angular $watch is a stream of model changes Angular also has an eventbus system : events on a handler are a stream Rx.Observable.$watch(scope, 'name') .map(...) .subscribe(...)
43. In real life with... Backbone.js Binding to an object is listening to it’s changes. This could be used as a stream. Rx.Observable.fromEvent(object, ‘click’) .map(...) .subscribe(...)
44. In real life with... JS Wokers A worker could post messages to into stream Rx.DOM.fromWebWorker('worker.js') .map(...) .subscribe(...)
45. Thanks! Any questions? We are hiring! Drop me a line at hugo@melusyn.com or @HugoCrd ♥
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