It must be obvious by now the value I put on schema, but for om, where
you necessarily end up with large hierarchies it has saved my bacon
multiple times.
I think of it less to do with type enforcement (although obviously the
s/validate or (s/defn ^:always-validate) can do that) and more to do
with a very lightweight and composable form of documenting my
expectations.
For example, I have things like (from memory not code):
(def TreeFilter {:expanded-ids [s/Num]})
(def SelectableTreeFilter (assoc TreeFilter :selected-ids [s/Num]))
;; unfortunately Clojurescript schema can't self refer - boo :).
(def TreeNode {:id s/Str :text s/Str (s/maybe :children) [s/Any]))
(def world (atom {}))
(def TreeComponent {:filter (merge TreeNode SelectableTreeFilter)
:node TreeFilter})
(s/defn ^:always-validate build-tree [data :- TreeComponent ...] (om/.....))
The sooner you use it the less painful it will be and almost every
single time I have gotten a stack trace it is because the data wasn't
as I expected. Coupled with Clojure's forgiveness of nils and empty
sequences it has been indespensible (e.g. a very high signal->noise
ratio).
On 5 January 2015 at 15:44, Arnaud Bailly <[email protected]> wrote:
> Thanks a lot colin for your insights. I will definitely take the time to
> investigate all that, and also stick to a more standard dual compilation
> approach as suggested by David.
>
> Some comments:
> - ok, schema looks cool! But then it makes me think why would I want to use
> a dynamically typed language like clojure if I can have a real type system
> with ghcjs...
> - yes, I also do enforce separation of biz logic from presentation stuff,
> unit testing the logic part. However the real point of UI component is that
> the DOM they produce depends on some state/interaction and this is that part
> I need to test, not biz logic
> - I don't use clojure for backend
>
> Cheers (and Happy new year)
>
> --
> Arnaud Bailly
>
> twitter: abailly
> skype: arnaud-bailly
> linkedin: http://fr.linkedin.com/in/arnaudbailly/
>
> On Mon, Jan 5, 2015 at 3:19 PM, Colin Yates <[email protected]> wrote:
>>
>> Hi Arnaud,
>>
>> Are you using lein cljsbuild auto? If so then :none should be sub-second?
>> Things that significantly improved my cljs workflow (with om):
>>
>> - figwheel (chestnut template is a great starting point) pushes
>> javascript changes to the browser (and css as well)
>> - defonce the atom so state persists figwheel pushes
>> - pristmatic's schema (or core.typed)
>> - pristmatic's schema (or core.typed)
>> - pristmatic's schema (or core.typed)
>> - pristmatic's schema (or core.typed)
>> - (yeah, realy, schema is that useful)
>> - pristmatic's schema (or core.typed)
>> - (I mean it :))
>> - https://github.com/cemerick/clojurescript.test (haven't tried David's
>> shiny new clojure.test port).
>> - ruthlessly separating out logic from components. If I need to unit test
>> a component I first see if I can split the interesting logic into a separate
>> method which I can test without a browser. If I can't then I go get some
>> coffee and try again.
>> - in a previous life (CoffeeScript and ExtJS) I had great times with
>> Jasmine.
>> - Cursive Clojure (https://cursiveclojure.com/). To be honest you might
>> want to stick with LightTable if it isn't clj backend.
>> - https://github.com/noprompt/lein-garden (but I suspect you might be
>> using a non-clojure CSS generator?)
>> - https://github.com/gdeer81/lein-marginalia for documentation
>> (https://github.com/zcaudate/lein-midje-doc also looks awesome but I haven't
>> used it).
>>
>> And did I mention schema? :).
>>
>> For general programming I highly recommend https://github.com/jonase/kibit
>> and https://github.com/jonase/eastwood.
>>
>> Hope this helps.
>>
>> On Friday, 19 December 2014 15:18:30 UTC, Arnaud Bailly wrote:
>> > Hello,
>> > I have been developing with Om and clojurescript for a few months now,
>> > and I do feel I am missing something to get as productive as I am when
>> > working with Haskell (or java for that matter).
>> >
>> >
>> > I would appreciate some advices or pointers resources from more
>> > experienced people on how to get to the point where I can develop
>> > confidently, easily and with decent speed in clojurescript.
>> >
>> >
>> > Here are my main concerns and some experiences I can share to give more
>> > context:
>> > - compiler is slow: I have setup cljsbuild profile to use advanced
>> > optimisation which heavily slows down compiler. Even simple optimisation is
>> > rather slow. No optimisation is rather fast, but not that fast (several
>> > seconds...). Note that I "often" have to remove generated compiled file and
>> > target/ dir to get usable result when doing advanced optimisation,
>> > otherwise
>> > I got seemingly unrelated runtime errors in the UI
>> > - compiler is not very helpful in catching errors: Error messages are
>> > ok, at least better than default clojure and its sometimes huge stack trace
>> > (or is it something from cljsbuild?), but of course not having types means
>> > fewer errors got caught... This is not an issue when one has the fast
>> > feedback of the REPL but large compilation time makes it really unwieldy.
>> > This is particularly annoying in Om because it requires state to be
>> > stored in an atom which in some contexts can be manipulated directly and in
>> > some others need to be dereferenced... And it is very easy, at least for
>> > me,
>> > to forget/add an @
>> > - unit tests are hard: code is mostly Om/react DOM building and ajax
>> > requests, so pure unit testing is not really useful or would need too much
>> > mocking. There seems to be a testing framework for React but I could not
>> > really figure how to use it given react is actually encapsulated under
>> > Om...
>> > I tried to write unit tests manipulating DOM elements but got stuck on how
>> > to simulate a change event. My JS-fu is probably lacking here but although
>> > I
>> > was able to synthesize a click, it was not possible for a change.
>> > - I resorted to selenium tests, but of course those are fragile and
>> > slow and I would like to avoid having to fire a server for testing part of
>> > client application
>> > - I tried to LightTable, but not being able to use repl/instarepl means
>> > I am left with a text editor less powerful than emacs. I user LightTable
>> > with clojure code and found it really nice so I would like to be able to
>> > use
>> > for clojurescript too.
>> >
>> >
>> > As I said, I have been coding for a living mostly in statically (or not
>> > so statically) typed languages (Java, Haskell), but I have been using
>> > clojure for side projects in the last few years and I really enjoy coding
>> > in
>> > clojure. So when I discovered Om I was really enthusiastic about its
>> > capabilities and the way it expanded my horizon to make programming in the
>> > browser a more pleasing experience.
>> >
>> >
>> > But my coding flow is not satisfying, it takes a long time to iterate so
>> > I tend to do larger steps which creates bigger mistakes which take a long
>> > time to track... And I positively hate using a debugged, especially with
>> > optimised clojurescript compiled code :-)
>> >
>> >
>> > So this post is really not a rant at all, I just got the feeling I am
>> > not doing things the right way and would like to be enlightened by people
>> > more knowledgeable than me.
>> >
>> >
>> > Thanks in advance,
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> > --
>> > Arnaud Bailly
>>
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