During the presentation, I explained how to make Angular 2 apps faster. It's split in two section: infrastructure improvements and architecture ones.

3. HOW TO IMPROVE ANGULAR
2 PERFORMANCE?
Oleksandr Tryshchenko
Senior Front-end Developer, DataArt
tryshchenko.com

4. HOW TO IMPROVE ANGULAR
2 4 PERFORMANCE?
Oleksandr Tryshchenko
Senior Front-end Developer, DataArt
tryshchenko.com

5. 128

6. What is 128 hours
• 3 working weeks and 1 day.
• 4 / 5 of your yearly vacation plan.
• Some money.
• Put your option here.
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7. Agenda
• Why does performance matter?
• Why do we need to tweak Angular 2?
• Problems we need to solve
• Solutions
• Conclusions
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8. What can we improve?
• Bundle size
• Application performance
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9. Infrastructure Improvements
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10. Bundle size: problem
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Not optimized FE 2752kb
Images Fonts HTML Scripts CSS

11. Bundle size: problem
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Optimized FE 822 kb
Images Fonts HTML Scripts CSS

12. Bundle size: problem
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0 50 100 150 200 250 300 350 400
2.5 Mb
1.5 Mb
0.5Mb
Loadingtime
56,6 kbit/s 1 Mbit/s 5 Mbit/s 50 Mbit/s

13. Ok. Why does it matter?
80% of internet users own a smartphone. (Smart Insights)
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14. …
Over 50% of smartphone users grab their smartphone
immediately after waking up. (ExpressPigeon, 2014)
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15. …
Google says 61% of users are unlikely to return to a mobile
site they had trouble accessing and 40% visit a competitor’s
site instead. (MicKinsey & Company)
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16. Ok. Why does it matter?

17. How can we reduce the bundle size?
• Compress pictures
• Minify styles, templates and scripts
• Remove useless code
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18. Handling images
• gulp-image-optimization
• gulp-image
• gulp-imagemin
• image-webpack-loader
…
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19. Handling styles
• A variety of Webpack loaders
• Angular CLI supports it by design
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20. Handling scripts
• A variety of Webpack loaders
• Angular CLI supports it by design
• … it is still huge. So we need to remove useless code.
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21. Tree Shaking
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0 500 1000 1500 2000 2500
Application 1
Application 2
Optimization Results
Before Tree Shaking,Kb With Tree Shaking,Kb

22. 26 April 2017 22
🎄👋

23. 26 April 2017
Tree Shaking
- Webpack marks useless code
- UglifyJsPlugin removes the code

24. How does tree shaking work?
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25. How does tree shaking work?
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26. How does tree shaking work?
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27. Tree Shaking
• For the moment Angular CLI has problems with tree
shaking.
• Use the latest version of Angular CLI.
• You need TypeScript 2 and WebPack 2.
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28. Compilation
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29. Compilation
• Just In Time Compilation (JIT)
• Ahead Of Time Compilation (AOT)
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30. What is JIT?
• Compiles in the browser.
• No need to build after changes.
• Default compiler in Angular 2 CLI.
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31. Why is AOT better?
• You don’t need to load compiler anymore.
• Faster loading.
• Better runtime performance.
• AOT is more secure, because JIT uses eval.
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32. AST (Abstract Syntax Tree)
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Script
Container
Members Decorators
Container
Members Decorators
Container
Members Decorators

33. AOT (Ahead Of Time Compilation)
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0 0.5 1 1.5 2 2.5 3
Bundle size, mb
AngularCLI defaultprojectsize
Compression,tree shaking and AOT
Compression with Tree Shaking
Raw

35. What can we improve?
• Bundle size
• Application performance
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36. Architecture Improvements
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37. Does architecture matter on
Frontend?
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38. What we can achieve with good
architecture?
• Better application performance
• Fewer API requests (app drives faster)
• Faster loading speed
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39. What architecture features are we
talking about?
• Make sure we’re using events efficiently.
• Make sure our data layer uses data efficiently.
• Control assets loading process.
• Organize correct components composition.
• Reduce DOM overhead.
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40. Problem: Army Of Listeners
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41. Solution: Change Detection
Strategies
• OnPush
• Default
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43. Change Detection Strategies
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45. Immutable ☺
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46. Mutable 🙁
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47. I wanna more!
26 April 2017 H T T P : / / W W W . J V A N D E M O . C O M / H O W - I - O P T I M I Z E D - M I N E S W E E P E R -
U S I N G - A N G U L A R - 2 - A N D - I M M U T A B L E - J S - T O - M A K E - I T - I N S A N E L Y - F A S T /
47
HOW I OPTIMIZED
MINESWEEPER USING
ANGULAR 2 AND
IMMUTABLE.JS TO
MAKE IT INSANELY
FAST
JURGEN VAN DE
MOERE

48. Immutable.js
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49. What to do with events?
• Use correct lifecycle hooks in the app.
• Be careful with your own events and use destructors.
• Avoid duplication of events.
• Avoid creation of useless events.
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51. What can we do with a data layer?
• Store static data in the browser. (Caching)
• Use pure RESTAPI (With HATEOAS)
• Use debouncing. Really.
• Background services.
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52. HATEAOS
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53. Why HATEOS?
• You don’t need to handle user roles on Front-End
anymore. At all.
• Server does it anyway during request/response cycle.
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54. 26 April 2017
ReactiveX (Rx.js)
• One more way to organize the
asynchronous actions using JavaScript
• Leads to a new way of the components’
composition.

55. Problem: XHR Overhead
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56. Rx.js + A2
PROS
- Allows us to remove HTTP logic from the components.
- Absolutely simple
CONS
- Leads to a new way of the components’ composition.
- It isn’t a fastest solution.
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57. What Can We Do With Component’s
Composition?
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58. Components Composition
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59. Problem: Memory Leaks
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60. Solution: Zone.js, ngZones, Data
Composition
• Dying zone will remove the subscriptions for local
streams, but won’t do it to current ones in service, upper-
level components.
• Use ngOnDestroy lifecycle hook for removing such
subscriptions.
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61. Zone.js, ngZones, Data Composition
26 April 2017 H T T P S : / / G I T H U B . C O M / A N G U L A R / Z O N E . J S / 61

62. Problem: Binding Overhead
• A simple rule: don’t use two-way binding when you don’t
need it.
• ‘Singular’ binding isn’t shipped out of the box, but there
are several ways to implement it.
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63. One-directional «inside»:
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64. One-directional «outside»:
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65. Two-directional:
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66. Problem: DOM
• Don’t use DOM 🙁
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67. What to with the DOM?
• Remove and add the elements back instead of hiding /
displaying.
• Don’t call DOM directly if it’s possible.
• When it isn’t possible use ElementRef,
@ViewChild/@ViewChildren.
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68. THANKS!
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