w/o callback Presented by: Khoa Tran

Jan 7th 2014

Agenda

• Why I don’t like callbacks

• Is there good alternative to write async code?

• Generator

• Get rid of callbacks

Why I don’t like callbacks?

1. Lots of nesting functions

2. Variable scope confusion

3. Handle exceptions everywhere

Writing readable code is hard!!!

Is there good alternative?

• Async

• Fiber

• Promise/Q

• Co

Generator • “In computer science, a generator is a special routine that can be

used to control the iteration behaviour of a loop” - From wikipedia

Executor Generator

…

next()

process val1

…

yield val1

next() …

yield val2 process val2

…

val1

val2

Generator in node.js

• Only supported in version 0.11.x and above. For

now, you have to build and install node.js from

Github.

• In addition, execute code with --harmony flag.

Get rid of callbacks

Clone demo source at:

https://github.com/tvkkpt/jsmeetup-demo

What to do next

Join this open-source project:

https://github.com/visionmedia/co

About us

Author: Khoa Tran

Find me at: tvkkpt@gmail.com

Presentation made for JavaScript HCMC Meetup

You can find us at: http://www.meetup.com/JavaScript-Ho-Chi-Minh-City/

https://www.facebook.com/JavaScriptHCMC?ref=hl

https://plus.google.com/communities/116105314977285194967

Thank you and HAPPY NEW

YEAR!