Javascript/Ajax questions for rails applications

I am loving just about everything in rails right now. I find a lot of
things faster than java and it’s a pleasure to work with.

One area though that I am not sure how to proceed with is ajax/
javascript.

For those of you using rails and a lot of ajax, what are your thoughts
on the built-in functionality for javascript? What about jquery-rails?
Do you go with it? Do you fight against it? Do you start from scratch?

With 3.1 having so many changes when it comes to Javascript, does it
make sense to setup your 3.0.7 project in a certain way to make it
easier to upgrade later?

There are also a lot of possibilities with other libraries on top of
jquery. For example, some people recommend using something like
backbone.

I have found on my last java program that require.js was really handy,
but I’m not sure if that was the ‘best’ way to structure large
applications. It was definitely better than doing it ad-hoc and just
sprinkling 10 script tags on every page.

I’d like this project to have some cohesion and structure when it
comes to how I lay out my javascript this time around. The javascript
features are going to be really intense, and I don’t want to run into
any pitfalls.

What would you suggest? While I am really experienced in developing
applications, I am not the most experienced when it comes to ajax-
specific ones. I am also pretty new to rails… so if there’s common
conventions and common library setups that everyone “just uses”, I
won’t be aware of it right now.

Thanks for the help.

On Sun, May 15, 2011 at 12:20 PM, egervari [email protected]
wrote:

I am loving just about everything in rails right now. I find a lot of
things faster than java and it’s a pleasure to work with.

One area though that I am not sure how to proceed with is ajax/
javascript.

For those of you using rails and a lot of ajax, what are your thoughts
on the built-in functionality for javascript? What about jquery-rails?
Do you go with it? Do you fight against it? Do you start from scratch?

Given that I knew very little about ajax and jquery when I started
working
with rails I have never touched the built in rjs and probably never
will. Up
to now it has just never seemed necessary and another place that
something
could go wrong. Definitely use jQuery if you have not already. That is a
level of abstraction that is a lifesaver.

You might want to jump directly to coffeescript (use the barista gem).
It is
the rubyfication of javascript and makes coding client side both fun and
productive again and will be part of rails 3.1. It works more than
nicely
with jquery too. Take a look at this presentation if you aren’t
convinced
yet: http://coffeescript-seattlejs.heroku.com

Martin

On Sun, May 15, 2011 at 10:20 AM, egervari [email protected]
wrote:

With 3.1 having so many changes when it comes to Javascript, does it
sprinkling 10 script tags on every page.
won’t be aware of it right now.
http://groups.google.com/group/rubyonrails-talk?hl=en.


Martin W.
p: +1 310 773 7346

I blog at http://martinatsunset.com
Follow me on twitter at http://twitter.com/martin_sunset . Learn more
about
me http://about.me/martinw.

Coffeescript is very sensitive to whitespace, and it does not support
!==
and ===
if you have that in your code that might be a reason for the error, cost
me
an hour today:)
Why don’t you post your code in a gist so that we can take a look at it?

Martin

On Sun, May 15, 2011 at 3:08 PM, egervari [email protected]
wrote:

almost, but I ran into 1 little snag.


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Martin W.
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Follow me on twitter at http://twitter.com/martin_sunset
Learn more about me http://about.me/martinw

Coffeescript is very sensitive to whitespace, and it does not support !==
and ===
if you have that in your code that might be a reason for the error, cost me
an hour today:)
Why don’t you post your code in a gist so that we can take a look at it?

Martin

Well, I have 2 scripts so far. One is ‘tour.coffee’ and the other is
‘dynamic_menu.coffee’.

Whenever I make a change to ‘tour.coffee’, everything works just fine

  • it will compile over and over again as I make changes.

However, if I make a change to ‘dynamic_menu.coffee’ - a file that
isn’t being directly loaded yet - that is when I get the compile error
(regardless of what is in this file).

https://gist.github.com/973664

I don’t know if this dynamic_menu.js works - I haven’t bothered to
really test it. But the overall point is that I can put:

alert "Hey"

… and it will still have a compile error.

Is there a better way I can do dependencies? ‘tour.js’ is supposed to
depend on this dynamic_menu.js. I would have used require_jquery.js
before, but I don’t think I can use that with coffeescript anymore.
However, if coffeescript can include them internally, then that would
be fantastic and might solve this compiling problem in one go.

Actually, to be honest, I get compile errors when I work with
tour.coffee directly. Anything non-trivial and Barista just isn’t good
errors - it’s not giving ANY errors.

Is this normal? Is the coffeescript compiler just a pure “yes/no”
syntax checker? If so… I really don’t think I can use it. I really
want my tools to help me out and give me good feedback.

I really hope I am just doing something wrong. I don’t think this is a
question of whether I am writing good or bad coffeescript… I think
something more fundamental is just wrong with compiling and giving
good errors.

You might want to jump directly to coffeescript (use the barista gem). It is
the rubyfication of javascript and makes coding client side both fun and
productive again and will be part of rails 3.1. It works more than nicely
with jquery too. Take a look at this presentation if you aren’t convinced
yet:http://coffeescript-seattlejs.heroku.com

Martin

I have coffee-script and barista installed. I got everything working
almost, but I ran into 1 little snag.

Whenever i make a change to a .coffee file… Barista does the right
thing and attempts to compile all of my .coffee files automatically.
This is cool.

However, I always get a compile error - even if the syntax should is
correct and the script is very simple. The compilation error doesn’t
say anything specific about what went wrong either. It just says:

Barista::CompilationError

Error: In app/coffeescripts/lib/dynamic_menu.coffee, V8::JSError

Rails.root: /home/egervari/Projects/training

The strange this is… if I restart the server, everything is fine
again. When I go to make 1 change to the .coffee file - ANY change at
all - this error rears its ugly head again, even though the syntax is
100% okay.

Any reason why it would be doing this?

Quoting egervari [email protected]:

I am loving just about everything in rails right now. I find a lot of
things faster than java and it’s a pleasure to work with.

One area though that I am not sure how to proceed with is ajax/
javascript.

For those of you using rails and a lot of ajax, what are your thoughts
on the built-in functionality for javascript? What about jquery-rails?
Do you go with it? Do you fight against it? Do you start from scratch?

Unless you have a lot of existing RJS, don’t use jquery-rails. It is
not
being maintained and is still at jQuery 1.3. IIRC, jQuery 1.6 has been
released. jquery-rails was a nice transition point for moving from RJS
and
Prototype to jQuery. Having done that, I am going to convert all the
RJS to
straight jQuery and/or move to Coffescript. At this point, unless
jQuery-rails is updated from the newer jQuery releases, it is useful
only as a
transition of existing RJS. Don’t write new code for it.

HTH,
Jeffrey

Yeah, I add lines like:

  i = 3 + 4

… just anything random and it’s causing these “compilation errors”.

I can’t use coffeescript if this is what it is like to develop using
it. Please tell me I have it setup wrong. If the coffeescript parser
can’t give good feedback as it compiles to javascript, then I am
positive it would set developers to a productivity loss rather than a
productivity gain.

On top of this, my internet connection has died 2 times today as I try
and find answers… Ubuntu 11.04 has constantly removing my minimize/
maximize buttons on my windows… and I had to reboot several times
for other misc. problems with linux.

Overall, today has just been a really bad day for development. It
doesn’t seem like anything is ‘just working’ :frowning:

Just to help investigate the issue: I have exactly the same
compilation errors.

My configuration:
rails 3.0.7
jquery-rails
barista
webrick
haml
compass
Ubuntu 11.04 (but I have no problems with Internet or minimize/
maximize buttons, only this coffeescript error)

Is this normal? Is the coffeescript compiler just a pure “yes/no”
syntax checker? If so… I really don’t think I can use it. I really
want my tools to help me out and give me good feedback.

I don’t think coffeescript is a yes/no compiler. On their webpage
http://jashkenas.github.com/coffee-script/
in try coffeescript tab, if you make syntax error, compiler will tell
you exactly the line number and type of your mistake.

So, maybe problem is with barista gem?


http://blog.eugen.co

Hi,
Not sure if I should start a new thread with the original question for
this one… this thread branched off to coffee script, I think it will
be awesome if we can get the sentiments of the folks here about the
questions put forth…

I don’t know much about coffee script, and I am a follower in Rails
having not migrated to Rail3 either. What I know is that I don’t like
going around the bush of things, and coffee script is that for me. So, I
want to use JS directly.

The question is: what is Rails’ strategy for Javascript? I don’t think
hiding it with things like RJS/CoffeeScript will yield good performing
apps. I am personally working to leverage JS directly, which gives me
the freedom at the client-side and the performance too. However, I am
not leveraging Rails enough that way. I, for example, use the Dojo
library; which is awesome for building a large app, though there is not
interworking with Rails that I know of. The original question above
mentioned libraries like backbone, require.js, etc. And in the mobile
space there is embed.js and others…

While I have Rails Conf videos on my TODO list to watch soon; can anyone
elaborate on what the direction is?

Coffeescript does not impact performance, not at all. It translates
directly
into javascript statements but takes the annoying parts, like
prototype definitions and checks for undefined, out of it.

Here is a sample I did to show you the difference between the code. You
will
see that the javascript that is the compilation result is quite close to
how
it would have been written if done by hand.

Coffeescript https://gist.github.com/979717
Javascript https://gist.github.com/979725

The original poster asked, among other things the following:

With 3.1 having so many changes when it comes to Javascript, does it
make sense to setup your 3.0.7 project in a certain way to make it
easier to upgrade later?
I am quite new to the rails world, but even for me it is obvious that
coffeescript combined with jquery will be the client/ language/lib of
choice
in Rails 3.1 and that RJS is dead. So it is sensible to start right now
to
develop future code in jquery and coffeescript, which directly answers
the
above question.

I also believe that backbone.js will be the winner for MVC for web based
apps. Can’t speak for mobile though

To answer another question: I pretty much ignore the built in ajax
functionality, except for the delete functionality, which is nice. I use
jammit and jammit-s3 instead of something like require.js, and
personally I
hope to use it in 3.1 as well. I also use backbone and coffeescript
together
to easily modularize my apps.

On Wed, May 18, 2011 at 3:07 PM, Mustafa C. [email protected]
wrote:

While I have Rails Conf videos on my TODO list to watch soon; can anyone
[email protected]
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.


Martin W.
p: +1 310 773 7346

I blog at http://martinatsunset.com : O API Marketplace, Where Art Thou
Follow me on twitter at http://twitter.com/martin_sunset

Same thing happens to me. I’ve taken to using ‘rake barista:brew’
which makes everything work again. Faster than restarting the server
at least…

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