but actually, for something like a NodeList, there's likely a utility somewhere that already does this...

yeah, I was thinking there would be a utility.

Any suggestions on anything that I could read further to understand this process a little better?

@tkjone did you see this? https://github.com/lynaghk/c2/issues/43

I quickly reviewed, but I am so new to clojure that some of it goes over my head lol. I will read through more carefully

nvm

I see what they are doing

(extend-type js/NodeList
    ISeqable
    (-seq [array] (array-seq array 0))

how's cljs for the backend?

I want to put up a simple site without the ram consumption of the jvm

as a following to my question yesterday, I got Preact working without framework; posted the simplest example here: https://github.com/mathieulegrand/Preact-with-ClojureScript-and-no-framework – will be trying to make it look cooler now

@mathieu I’ve been playing with Preact+CLJS a while ago, unfortunately Preact doesn’t support ES6 Iterable protocol that is used in ClojureScript to iterate over data structures, which doesn’t allow to render collections of components easily

you’ll have to convert cljs collections of child nodes into JS arrays before passing them to Preact

@symfrog I cannot reproduce the problem with the first repo from yesterday - React loads fine, no errors

@dnolen It fails silently to load the module, the error can be seen in Chrome when "Pause on caught exceptions" is ticked under Sources in Chrome DevTools

@symfrog I don’t see this

React loads fine

it’s there and I can reference it

I tried many different thing - no issues

I will add this was one of the very first things I tested when I developed :modules

btw

odd, I get the issue on a clean clone with Chrome 60.0.3112.90, will see if there are other environments I can reproduce it on

if you mean you only see the error when you click Pause on caught exceptions

then I don’t see how that’s relevant

how the loading Closure module machinery works is not our concern

I’m on Chrome 60.0.3112.90 OS X

Same environment on my side, I can see the module manager failing to load the module and attempting retries, so the module is failing to load, might be something else specific to my environment, will continue to look

@dnolen On my side the issue also occurs on Safari (10.1.2) and Firefox (55.0), is this the repo you are using https://github.com/symfrog/cljs-modules-react ?

@symfrog I cloned your repo

and I don’t really have any more time to look at this

I’m now looking at the order bug

ok, thanks for checking, I will continue to check for something specific on my side

fwiw, other people have tried this feature with foreign-libs React and nothing has been reported

it’s not to say that there isn’t an issue but it’s hard to know what’s going on

I have found it only occurs when using optimizations :none

it would preferable that you can repro with something more minimal

@symfrog people are testing with all the optimization settings

including myself

by more minimal - I mean make something w/o Lein

React is not relevant here

ok, will do

Quick Start Uberjar is the only thing you should be using

@symfrog I do see the foreign-lib order issue

not a show-stopper for this case, since nothing breaks

but looking into fixing this since this would affect other libs

@dnolen fwiw, React is available for the first issue, but the module manager considers the module to have failed to load and the module loaded callback is not called, the module manager invokes the error handler

If the module loaded successfully, you should see "Module B init" in the console

right this is the kind of information that should be in the repo

otherwise I spend a lot of time

yes, sorry, should have added that

https://dev.clojure.org/jira/browse/CLJS-2309

@symfrog found the issue, https://dev.clojure.org/jira/browse/CLJS-2310 thanks

great, thanks

Still looking for a custom JSON serialization method that doesn’t require a consumer to know transit. Is there such a thing?

@alex-dixon what are your requirements?

Fast as possible. Publicly consumable as possible. Convertible to EDN. Data may contain compiled Clojurescript functions, so I’d like to test for that and supply a map with information about the function instead of the default #object reader tag that is generated for them.

@alex-dixon as long you don’t use the more complex features, I don’t see the problem with Transit

there’s a verbose mode

Oh…

Looking here https://github.com/cognitect/transit-cljs/wiki/Getting-Started#writing I thought the "~:some-keyword" was transit-y. I guess I could deal with it but is there an option to stringify keywords without the tilde?

@alex-dixon I think that would be the only issue, but to me if you want JSON why bother keywords anyway

there’s nothing particularly idiomatic about kebab case

we've recently had significant performance problems relating to consuming JSON. We did these steps: - JSON.parse - js->clj - turn string keys into keywords - kebabize-keywords That turns out to be really slow

What helped was to give up on kebabization and to use string keys rather than keywords

It's not too painful because you can use {:strs [abc]} and just replace keyword calls with get

good rule of thumb, if you want speed, stop creating pointless marshalling steps just to make things “easy”

However we did not remove the js->clj step although that is a performance bottleneck. The reason we kept it was that working with mutable data structures is more painful

@pesterhazy fwiw, you could probably use Transit verbose JSON reading

To do that you'd have to use gobj/get instead of get, and you can't assoc/update etc.

I suspect at least an order of magnitude faster to marshal than js->clj

@dnolen, interesting. We'd need to update the Golang api for that

http://swannodette.github.io/2014/07/26/transit-clojurescript

🙂

Hadn’t considered the key encoding issue really. Thanks for pointing that out

Oh wait, reading the blog post... does Transit's verbose mode work with any JSON? That is, the produce doesn't have to be transit-aware?

yes

modulo collision, i.e. some JSON value starts with “~CHAR…”

that's fantastic... and not a very widely known fact

well I did mention it 3 years ago 🙂

fair point

I'm going to give this a try and report back

@pesterhazy I’m not following “The produce(r?) doesn’t have to be transit-aware”

You can just consume any kind of JSON using the transit reader - it doesn't have to be JSON-encoded transit.

Oh!

(Unless you have weird keys starting with a tilde character, which you most likely do not)

At that point is it just leveraging MessagePack or something?

:thinking_face:

But…point being faster reads from any valid JSON minus tildeized keys with transit reader

not MessagePack, no

not sure why the transit reader is so much faster than JSON.parse+js->clj

Is it because it produces less garbage? Shouldn't JSON.parse be pretty much optimal?

JSON.parse is fast, js->clj is not

Frustrating that CLJ/CLJS doesn’t rule the world sometimes

js->clj could be made faster of course, but since Transit solves a more general problem - it’s not really worth the effort

(->> raw JSON.parse js->clj count time), 1000 runs, 5445 msecs
(->> raw (cognitect.transit/read rdr) count time), 1000 runs, 2683 msecs

transit/read is significantly faster

Hey guys, using the new npm integration I started integrating the new google material components https://github.com/material-components/material-components-web to react using clojurescript. It is still a prototype but who knows, someone might be interested in playing with what I got right now and give me some feedback. You can find the code here https://github.com/JeremS/material-cljs cheers

Hi all! I just started with clojure/clojurescript and run into the issue of: >WARNING: Use of undeclared Var om-tutorial.core/dosync at line 117 /home/elias/Testing/om-tutorial/src/cljs/om-tutorial/core.cljs When trying to use dosync. I cannot find any reference on how i should import that - it pretty much looks to me like it should be imported by default, so i wonder why i get this warning

For reference, here is the code in which i try to use it:

(defmulti mutate om/dispatch)
(defmethod mutate 'board/evolve
  [{:keys [state] :as env} _ _]
  {:action
   (let [temp-board (:temp-board state)
         new-board (evolve (:board state) temp-board)]
     (dosync
      (swap! state assoc-in [:board] new-board)
      (swap! state assoc-in [:temp-board] (generate-temp-board new-board))))})

@alpox dosync doesn’t exist in ClojureScript

@dnolen Ahh, thanks, that explains a lot 😄 does one just use do instead?

JavaScript is just single threaded, there’s no need for dosync

dosync ref if they existed would only be for portability - if somebody wants to provide a patch for that, would be welcome

@dnolen i was thinking about that but then again i don't know how clojure/clojurescript works below and what exactly these functions do in the end. Many thanks for the clarification 🙂

@alpox if you have om specific questions you might want to ask in the #om channel

@dnolen :thumbsup: thanks again

@alpox If I may you might also want to update your state in a single swap! if you want the update to be atomic. I won’t really matter in clojurescript since javascript is single threaded but it might in clojure. You might do it like this

(swap! state #(-> % 
                    (assoc-in [:board] new-board)
                    (assoc-in [:temp-board] (generate-temp-board new-board)))))

@jeremys you may! I'm always interested in the best and better way to do things 🙂 after all, i just arrived and am learning 😄

Thanks for the suggestion, i will gladly use this

@alpox welcome

@alpox @jeremys I think for the purposes of assoc‘ing several values into a structure, you can just use assoc - that is, if your path is only one level deep.

(swap! state assoc :board new-board
                   :temp-board (generate-temp-board new-board))

@reefersleep I didn't see that i can use multiple associations 😄 thanks for that

Enlightenment about the threading macros is essential, though, so I find @jeremys example and mine complementary 🙂

np

Hello all, any suggestion for web app functional testing tool? I need to validate some states of external website and I want to do it automated with clojure. Do you think is it a good choice using clj-webdriver and PhantomJS?

@alpox @reefersleep of course assoc is way better there!

i'm trying to import the blocking pipeline to my clojurescript REPL

(require '[cljs.core.async :refer [<!!]])
----  Could not Analyze  <cljs form>   line:1  column:1  ----

  Invalid :refer, var cljs.core.async/<!! does not exist at line 1 <cljs repl>

@lilactown you cannot possibly have blocking functionality available in javascript

ah, gotcha 😕

this is probably well documented somewhere 🙂

i honestly am struggling to find documentation for cljs.core.async

this is a solid answer: https://stackoverflow.com/questions/21400464/cant-seem-to-require-or-in-clojurescript

yeah, I saw that but wasn't sure if things had changed since 2014

javascript has only a single thread, you cannot block it, this is not going to change anytime soon 🙂

mm. sure, I can imagine now that it would be incredibly awkward to emit code that replicated that behavior.

I just wish there was a way that I could do psuedo-blocking stuff in the REPL

nbd. thanks for the response 🙂

what is the correct way to include scoped packages with :npm-deps?

https://docs.npmjs.com/getting-started/scoped-packages

How do I call a method definition on a prototype? I’ve tried

(goog.date.Date.prototype.toUTCIsoString (new DateTime))
(apply goog.date.Date.prototype.toUTCIsoString [(new DateTime)])

TypeError: this.getUTCFullYear is not a function
    at goog.date.Date.toUTCIsoString (/.cljs_node_repl/goog/date/date.js:1234:10)

@lvh shouldn’t the . before toUTCIsoString be a / ?

goog.date.Date.prototype isn’t a namespace so I don’t think so

I’m thinking static method syntax

also goog.date.Date.prototype.toUTCIsoString evals to a fn as you’d expect

maybe those things don’t work like static methods though

OK

@noisesmith FWIW I just tried it and it broke saying that’s not a ns

so these things work

(cmd)dev:cljs.user=> (.-length (.-prototype js/String))
0
(ins)dev:cljs.user=> (.-length "foo")
3

and

(ins)dev:cljs.user=> (.charAt "foo" 1)
"o"
(ins)dev:cljs.user=> (.charAt (.-prototype js/String) 1)
""

I think you just access the item on the thing and ignore the prototype? I could be misunderstanding your issue

you need to set the this via .call .apply or .bind

cljs.user=> (js/Date.prototype.toISOString.apply (js/Date.))
"2017-08-08T22:59:17.973Z"

ah; I did apply instead of .apply. Derp. Thanks sundarj 🙂

np

cross post from emacs: does anyone here use emacs and have a preferred html/css mode?

figured its worth asking here since i only find myself in html when working on cljs things

I tend to use garden for css, and hiccup for html, then everything stays in clojure mode. 🙂 I do have an extra index.html that is hand written, but I almost never change it.

fair enough!

thanks

i did just stumble upon web-mode

but i suspect i won’t touch html that often either