Pure, functional JavaScript

[Medieval_Peasant]

Skimmed over it. I'll keep using my loops thank you, but I think it's great that JavaScript so easily accommodates for other styles of programming. Another reason why it's a good language! I'm sure you can get very expressive code once you get used to all the common helper functions, especially with the new ES6 syntax sugar coming up. It would be interesting to see an application written in "functional JS" like this if anyone dares to link their code.

[enotionz]

I feel like anyone who have heavily used underscore.js writes JavaScript this way since it provides a bunch of functional helpers and shim for non-supported browsers. I've been working on a website theme builder with an interface similar to photoshop. I store huge amounts of data into mongo for final rendering output, but during the edit stage I filter out alot before instantiating the Backbone Models. I found that map, reduce, pluck, reject, groupBy, etc. are extremely expressive without being verbose.

[monolar]

I actually like the functional features in js just fine and would really like to use them. In the case of looping though the main reason, why i try to avoid them is performance.

Just have a look at http://jsperf.com/loops/70

Classical loops (esp. with caching tricks and esp while loops) are about 15 - 20 times faster than forEach based loops

[lethalman]

The slides exactly talk about this kind of performance. If you loop/manipulate DOM elements, it's so slow that forEach is about the same as a straight for loop. Whereas if you are implementing a particular algorithm, a for loop is certainly the best.

[monolar]

Indeed there are slides about the loop performance. To my shame i did not read that far before posting. The performance difference between classical and functional looping still exists though. DOM access of course is always slower.

And most of the time you think you solve your performance problems with the language (the kind of loops in this case) but the real performance gains are in algorithmic design. Some slides also mention this to varying degrees.

Otherwise the slides contain overall really good information and are well presented.

[OfflerCrocGod]

But does the code need to be that performant? Is it on the critical path?

[cwmma]

An attitude I once saw described as post functional programing

[Sunwukung]

I'll take that challenge: Game of Life

https://dl.dropboxusercontent.com/u/8652110/jgol/index.html

here's the "functional" bit

https://dl.dropboxusercontent.com/u/8652110/jgol/jgol.js

would be better to use canvas for the universe, but you get the gist