Re: Node and callback hell

[Pete Helgren <pete@xxxxxxxxxx>]

Kevin,

Amen!  The hardest thing for me to wrap my head around was the 
asynchronous nature of AJAX calls.  Sure, you can make them synchronous, 
but my recommendation is to bite the bullet and get a clear 
understanding of it first, work with callbacks without entering "hell" 
and then look at promises.  Just trying to follow nested async calls 
would make my head hurt.  Just about everything in node.js and 
JavaScript libraries in general is asynchronous so yeah, "hell hath no 
fury like asynchronous calls ..."

Generators in ES6 looks promising (no pun intended) so it looks like the 
future is getting a bit more manageable when it comes to async 
processes. Here is an article (among many) about ES6 generators: 
http://chrisbuttery.com/articles/synchronous-asynchronous-javascript-with-es6-generators/

I love this stuff.  It just gets better and better....

Pete Helgren
www.petesworkshop.com
GIAC Secure Software Programmer-Java

On 10/23/2015 8:55 AM, Kevin Turner wrote:
> Hello
>
> Callback hell has been mentioned a few times (mainly by Nathan) and it is something that has been bugging me recently because I have indeed fallen into this trap.  It is also known as the "pyramid of doom" because your code can end up looking like an ever increasingly complicated list of nested function calls.
>
> However, mainly because Sails uses it "out of the box", I have educated myself in the use of "Promises".   Promises allow you to write your asynchronous code in a synchronous way, such that callback hell can be eliminated.
>
> I won't go into the details here, but if you are interested, look uphttps://github.com/kriskowal/q
>
> Waterline ORM also uses a promises library called "bluebird":http://bluebirdjs.com/docs/getting-started.html
>
> I have refactored a lot of horrific code now that I have a grip on this technique.....promises are beautiful thing!
>
> Kevin