This document provides an overview of the MEAN stack and how it can be used to quickly prototype and build web applications. It discusses how MongoDB, ExpressJS, AngularJS, and NodeJS work together to allow real-time data binding from the database to the client. The document also covers best practices for adapting applications based on feedback, automating testing, and scaling applications efficiently as they grow in usage.

1. Intro to the MEAN Stack
Using NodeJS to drive superheroic web apps
Valeri Karpov
Kernel Tools Engineer, MongoDB
thecodebarbarian.com
github.com/vkarpov15
@code_barbarian

2. Who is this guy?
CTO 2008

3. What does MEAN mean?
MongoDB - document database
ExpressJS - web framework for NodeJS
AngularJS - client MVVM, server ⇔ UX
NodeJS - event-driven IO in Javascript

4. What is this talk about?
- Building a new web app: its easy…
- … except when it isn’t
Expectation
Reality

5. The Problem Categories
Your problems look something like this:
Prototype. Build a usable product fast
Adapt. Iterate on feedback
Test. Automate testing using CI
Scale. Utilize server resources efficiently

6. Prototype
“Done is better than perfect.”
- Facebook developer mantra

7. Prototype
- Goal: Get usable product in users’ hands fast
- Success story: Ascot Project

8. Prototype
- Surface: one language makes life easier
- Surface: package management
- Deeper: tight binding from database to client

9. Start with a UI
Interactive client-side templating
Client-side: JSON bound to state of view

10. Server View of Data
Interactive client-side templating
Server receives JSON data as-is

11. Database View of Data
Interactive client-side templating
MongoDB stores JSON data as-is

12. Why is this useful?
- Lower barrier to entry for new devs
- Declarative UX
- Easier debugging
- Code reuse

13. Adapt
“There's a plaque on our wall that says we've
sold over 65 million albums, and I don't feel I've
accomplished anything. I feel like I'm just
getting started.”
- Eddie Van Halen

14. Adapt
- Application always starts out simple, but...
- REST APIs. Socket APIs. SMTP.
- How will you integrate with new tech?

15. The NodeJS Advantage
- Threads and locks are difficult
- Cron jobs are difficult
- Your server needs to be concurrent
- NodeJS provides easy, testable concurrency

16. Best Case Scenario
- Bitcoin arbitrage from apartment
- 1 hour from nothing to live trading
- 15 minutes to add a new exchange

17. Test
“Beware of bugs in the above code; I have only
proved it correct, not tried it.”
- Donald Knuth, former Stanford CS Professor

18. The Challenge
How do you prove your code works?
Success story: Bookalokal

19. The Evolution of Testing
- Manual testing?
- Unit tests?
- E2E tests?
- Test runners?
- Continuous Integration.

20. MEAN Stack Advantage
- Javascript makes unit testing very easy
- Trivial dependency injection:
- AngularJS has built-in DI
- Lots of NodeJS DI, recommend
https://npmjs.org/package/omni-di

21. MEAN Stack Advantage
- E2E tests: angular-scenario

22. Karma test-runner
- http://karma-runner.github.io
- Launch browsers, run tests on file save
- Compatibility: angular-scenario, nodeunit,
jasmine

23. Karma and CI
- Jenkins: http://bit.ly/1fVqoC9
- Circle CI: http://bit.ly/1dhuR4A
- Travis CI: http://bit.ly/I3ojbF
- Semaphore: http://bit.ly/IgiWFz

24. Scale
“Go Big or Go Extinct”
- Tagline to the 2013 film Pacific Rim

25. A Word of Caution...
Scalability is (mostly) a Maserati Problem
http://bit.ly/17gOvUO (Moderately NSFW)

26. Scale… to what?
- Difficult to judge exact number, say O(1000)
- Single machine
- 20% of mistakes 80% of new apps make
- Horror story: SCNVGR, 10/18/08

27. What are the key points?
- Don’t be Schlemiel the Painter

28. Bandwidth is scarce
- Is the browser caching static assets?
- Is your CSS and JS minified?
- Grunt everybody’s favorite minifier
- Bonus minify css/js on server start using
uglify-js.

29. Hard drive is slow
- Especially true on EC2 - not an actual HD!
- Is your database reading from HD?
- MongoDB: In-memory “caching” built in! :)

30. Don’t choke the CPU
- Is your server single-threaded?
- NodeJS: You get this for free! :)

31. A Common Criticism
Will MEAN be obsolete in 5 years? I hope so.
“To know ten thousand things, know one thing
well.”
- The Book of Five Rings by Miyamoto Musashi

32. Thanks for Listening!
Comments, questions, haikus?
Read more at:
thecodebarbarian.com
github.com/vkarpov15
@code_barbarian