I submitted a conj talk on cljs, hoping that this year is our breakout!

Cool

If anyone wants informal feedback from me on an abstract for the Conj, feel free to ping me

disclaimer: I am not involved with selection in any way

But I am good at feedback

hmmm I guess I should have put this in the general channel

well cross post

I’ll say something ClojureScripty while I am here

GO CLOJURESCRIPT!

Also, now that OS scripting is getting really close, please someone make a replacement for Ansible in ClojureScript

haha

ansible is great if you like writing all your logic in yaml

While migrating [garden](https://github.com/priyatam/garden/commits/master) (3000 LOC) from Cljx to Cljc, I'm stuck on few cryptic errors from cljs compiler 1.7.28. Any help appreciated!

here’s one:

Caused by: clojure.lang.ExceptionInfo: Assert failed: Argument to macroexpand must be quoted
(core/= (core/first quoted) (quote quote)) {:tag :cljs/analysis-error}
	at clojure.core$ex_info.invoke(core.clj:4593)

I get these errors while running node-repl.

Turns out I forgot to wrap a defmacro defn in :clj reader literal. If only compiler error messages could point out to the source of the problem ….

@pri: patches for better .cljc error messages welcome, hard to guess what people would encounter.

can you point me to the right source … as a starting point.

@pri: the stacktraces give you all the source locations that lead to the error

and every single function on the way

got it, my bad!

cljs.analyzer is where you want to look

you’ll see a bunch of multimethod cases for giving more humane errors

Back to the usage of cljc reader literals: what’s the idiomatic way of adding literals in extend-protocol

Here’s an example that is currently throwing an error:

(extend-protocol IExpandable
  #?(:clj
      clojure.lang.ISeq
      (expand [this] (expand-seqs this))
      clojure.lang.IPersistentVector
      (expand [this] (expand-rule this))
      clojure.lang.IPersistentMap
      (expand [this] (list (expand-declaration this)))
      Object
      (expand [this] (list this))
      :cljs
      IndexedSeq
      (expand [this] (expand-seqs this))
      PersistentArrayMap
      (expand [this] (list (expand-declaration this)))
      PersistentHashMap
      (expand [this] (list (expand-declaration this)))
      PersistentTreeMap
      (expand [this] (list (expand-declaration this)))
      default
      (expand [this] (list this)))

  CSSFunction
  (expand [this] (list this))

  CSSAtRule
  (expand [this] (expand-at-rule this))

  CSSColor
  (expand [this] (list this))

  nil
  (expand [this] nil))

error:

clojure.lang.ExceptionInfo: Feature should be a keyword: (expand [this] (expand-seqs this)) {:type :reader-exception, :line 274, :column 41, :file “/~/garden/src/garden/compiler.cljc"}

The cljx syntax [was simpler](https://github.com/noprompt/garden/blob/master/src/cljx/garden/compiler.cljx#L270)

The only way I can get this to eval is to create separate :clj and :cljs protocols and repeat the common elements in each. I’m sure there’s a better way ...

@pri: I don’t see why you don’t do two top level expressions

@dnolen: ex?

#?(:clj ….) #?(:cljs …)

instead of #?(:clj … :cljs …)

top level seems to be taking only one form

you also have #?@ for splicing but you can’t do that at the top level, but doesn’t really matter much IMO

I saw that in datascript but couldn’t understand. what does it splice?

https://github.com/tonsky/datascript/blob/master/src/datascript/core.cljc#L353

(trying your suggestion)

#?@(:clj [(def x 1) (def y 2)])

but again you cannot do this at the top-level

but that’s what it does

top-level as in ..

the top level

(do (defn foo []))

foo is not at the top level

(defn foo [])

is

got it

So i try this:

(:cljs
      LazySeq
      (render-css [this] (map render-css this))
      ….

I still get the error Feature should be a keyword: (render-css [this] (map render-css this))

What exactly does :cljs take? A form, forms … ? In this case I’m implementing protocols.

For simpler forms it’s easy, but I’m struggling with code that has protocols or defrecords implementing protocols

@pri: you haven’t figured out the conditional reading syntax

#?(:clj single-form :cljr single-form :cljs single-form)

I agree, I haven’t. I’m guesssing from code I read

@pri: if you stop guessing you’ll figure it out instantly

so here I am

you can only supply single forms

if you need multiple forms you need #?@ + vectors of forms

the caveat - #?@ doesn’t work at top-level

those are all the rules

but with extend-protocol, I’m dealing with multiple forms at each protocol level. Should I just wrap each and every protocol/impl? https://github.com/noprompt/garden/blob/master/src/cljx/garden/compiler.cljx#L270

Is there a way to avoid wrapping the reader literal at every protocol/impl level?

@pri: step back - I cannot see what problem you are trying to solve that I did not already answer

you can A) use two separate reader conditional expressions B) use reader conditional splicing

I do not understand how this doesn’t completely answer your question

if it doesn’t answer your question you need to be more clear how it doesn't

Hi, i'm trying to use reagent/set-state, but it seems that all my instance of the same component recieve the same reageant/set-state when i change it on only one of them

behind the sceen reageant use a var to keep the current component

I've stored this current component on a let binding at the beging of my reagent component function

So two questions, could we use reageant/set-state with reageant/hipcup plain function ?

Is the dynamic nature of the \var\ related to my issue?

If interested in getting hands dirty with Planck dev, I’ve started marking “newbie” issues: https://github.com/mfikes/planck/issues?q=is%3Aopen+is%3Aissue+label%3Anewbie

Hi, is using cljs.build.api in custom scripts now recommended over lein-cljsbuild? I got the impression that's the currently recommended practice. For example, the Clojurescript wiki doesn't recommend starting with lein-cljsbuild (https://github.com/clojure/clojurescript/wiki/lein-cljsbuild).

@benzen perhaps someone in #C0620C0C8 might know

I discovered this function by accident: is it intended for public use, if so, in what cases would one use it? https://github.com/clojure/clojurescript/blob/master/src/main/cljs/cljs/core.cljs#L9935

@borkdude: Hah, I was wondering the same when I noticed that Planck auto completes it for te

@jindrichm: that’s not what that page says, it’s not a recommended starting point

lein, boot, Maven, or nothing else at all are perfectly fine ways to work with ClojureScript

thanks @tomisme , didn't notice that there is a dedicated channel for reagent

bit of self-promotion - I wrote a Chrome extension in Clojurescript to help with code review on GitHub - https://github.com/smcgivern/gitique

and I very much like the usability of the build scripts, no lein or boot here, much less to think about when getting started

@dnolen

@dnolen: You're right. Do I read that correctly that recommended starting point is to use custom scripts using cljs.build.api?

Nice @mcgivernsa

@jindrichm: yes

@dnolen: Is it favoured as a starting point because it doesn't hide the complexity of the build process as lein-cljsbuild does?

@jindrichm: build scripts aren’t any more complicated then lein-cljsbuild

what it does is show you how it actually works so you can diagnose the issues 3rd party tooling tends to introduce

also we don’t take bug reports that involve 3rd party tools anymore

Yes, I very much agree with the build scripts being more transparent.

so if you want to file issues, it must be with ClojureScript only

OK, thanks for the clarifications.

another newbie friendly JIRA issue http://dev.clojure.org/jira/browse/CLJS-1393

https://twitter.com/roman01la/status/629309211097346048

wow https://github.com/clojure/clojurescript/commit/139da195125110646f8d5550fc753fdbf63f565c

kinda surprised no one asked for this before

node can be debugged?

news to me

@gtrak: for at least 4 years various reasonable debugging solutions have existed

but the above means for Cursive users and non-Cursive users you can get decent debugging of ClojureScript on Node

https://github.com/node-inspector/node-inspector

Is line 103 strictly good practice? A discarded side effect inside a let binding?

(it predates the commit, so if it's bad and it works it can't be that bad, but I've never seen that before)

Anyone else getting SyntaxError: Unexpected token ; when doing (declare x)?

Only getting it when calling declare with a single arg, works with 2+.

@martinklepsch: I suspect this is a REPL specific issue around :def-emits-var, \cc @mfikes

That’s the same as (def x)

It won’t work in a REPL.

@teslanick: I wouldn’t blindly copy any idiom you find in the ClojureScript compiler

uh, interesting, thanks!

@martinklepsch: Turn on :repl-verbose and you’ll see why.

@martinklepsch: I take that back… I think you need to actually debug things to see why. But in short it becomes a NOOP which fails for the JS emitted at the REPL. I think this has been the case for at least a year.

@mfikes: "Error evaluating:" (declare test-var) :as “” this made me understand

declare only modifies the compiler env but doesn’t actually emit anything

@martinklepsch: Here is the JavaScript sent to the engine for (declare test-var):

javascript
(function (){try{return cljs.core.pr_str.call(null,(function (){var ret__4371__auto__ = ;
cljs.core._STAR_3 = cljs.core._STAR_2;

cljs.core._STAR_2 = cljs.core._STAR_1;

cljs.core._STAR_1 = ret__4371__auto__;

return ret__4371__auto__;
})());
}catch (e7994){var e__4372__auto__ = e7994;
cljs.core._STAR_e = e__4372__auto__;

throw e__4372__auto__;
}})()

So it has to do with the REPL’s “wrapping” JavaScript to instrument *1 and *e resulting in the derailment.

@martinklepsch: You can work around it (and cause the compiler analysis metadata to be updated) by doing something like this (do (declare test-var) nil)

@mfikes: thanks that’s very handy!

It could probably be fixed in cljs.repl or in the compiler (which would be nicer for the case when :def-emits-var is enabled and you are doing something like (def x)), the challenge being perhaps knowing when to do it.

@mfikes: I’m currently trying to figure out if I can declare something with metadata but it seems not possible, is that correct?

@martinklepsch: To be honest, for something like that, I’d fire up lein repl and see how Clojure behaves.

@martinklepsch: And if you find something that works in Clojure but not ClojureScript. Don’t give up. (http://dev.clojure.org/jira/browse/CLJS-1333 for example)

Well it seems to work in none of them 😛

boot.user=> (declare ^{:w true} test-var)
#'boot.user/test-var
boot.user=> (meta test-var)
nil

@martinklepsch: Meta is on the var

user=> (declare ^{:w true} test-var)
#'user/test-var
user=> (meta #'test-var)
{:ns #<Namespace user>, :name test-var, :w true, :file "NO_SOURCE_PATH", :column 1, :line 1, :declared true}

@martinklepsch: That works in Planck

@martinklepsch: And in Ambly. So it works in ClojureScript and bootstrapped ClojureScript.

ugh, I’m so stupid 😄

@martinklepsch: No… you can have meta on collection values as well. Probably not what you meant but, nevertheless:

user=> (def x ^{:w true} [1])
#'user/x
user=> (meta x)
{:w true}

(Just saying that (meta test-var) is reasonable.)

yeah, that makes sense. Thanks!

I think the only other place meta can go is on symbols. (As in CLJS-1333.)

I'm trying to use the Google Maps Place Search API

I can successfully add a map (with the help of the reagent cookbook), and I feel like I'm really close with the Place Search

Just, you know, not quite there.

@martinklepsch: I’ll be putting together a patch for http://dev.clojure.org/jira/browse/CLJS-1397

When I try to implement

service = new google.maps.places.PlacesService(map);
service.nearbySearch(request, callback);

It fails with the error null has no properties

Function looks like:

(defn get-places []
  (let [lat 56.325760
        lng 44.004964
        center (google.maps.LatLng. lat, lng)
        map-opts (clj->js {:center center
                           :zoom 12})
        map-canvas  (.getElementById js/document "map-canvas")
        mappy    (js/google.maps.Map. map-canvas map-opts)

        request (clj->js {:location center :radius 10000 :types "['store']"})]

    (.nearbySearch (google.maps.places.PlacesService mappy) request 
                   (js/console.log (pr-str)))))

I'm expecting to get back an array.

Does anything seem obviously wrong with this?

@coyotespike: one thing that may be affecting it is that you're just calling google.maps.places.PlacesService but in the js example you showed there is a new which you don't seem to take into account

I am trying to use transit & cljs-ajax together, but i can't seem to read the json response correctly:

(def reader (t/reader :json))

(defn render-app [resp]
  (println (t/read reader resp))
  (q/render (App) (.getElementById js/document "app")))

(GET "" {:handler render-app})

@coyotespike: and another thing - your callback is missing a # to make it into a function. (js/console.log (pr-str)) isn't a function

I get an Unexpected end of input and an Unexpected string

@coyotespike: and not sure what you're doing with pr-str there

@jeremyraines: more information - what does resp print as before attempting to read it

@coyotespike: and, the api docs say that the request "types" option should be an array but yours is a string

@antishok: thanks for the suggestions!

I changed to #(js/console.log), and also tried using a plain array.

#(js/console.log) is a function that just calls console.log with no arguments

#(js/console.log %) would pass the first argument

[{name Pants, id 1339254, color_name Dark Gray, keywords joseph other pants joseph farfetchcom dark gray pants other pants female, large_default_image_url  {name Bag, . . .
 

Even that change isn't working

oh, I get it I think. cljs-ajax is already converting it to a clojure vector

I believe you initialize a new google.maps.placesService object by calling it, or assigning to a variable. The new isn't necessary.

I have a function that looks pretty similar, but just makes the map, and a marker on the map.

and that works...

@coyotespike: from a simple test i'm doing (in javascript) the new is needed

@antishok: yes, but not when it's translated into ClojureScript

did you get it to work in js?

@jeremyraines: yeah doesn’t look like JSON to me

not sure what you mean not when it's translated to cljs? in cljs you need to just add the dot, no?

@coyotespike: i just got this working in js, not really familiar with the api. http://jsfiddle.net/6aucyony/1/

oh, cool

Also, if you look at the translation here: https://github.com/reagent-project/reagent-cookbook/tree/master/recipes/google-maps

you can see how they "translate" to CLJS

new google.maps.Map(stuff) is tranlated to (js/google.maps.Map. stuff)

the dot after Map is the new

so in your code (google.maps.places.PlacesService mappy) should be (google.maps.places.PlacesService. mappy)

lol I was just typing in that I tried that and that error is gone!

yays

That is pretty exciting

:)

Thanks for helping me sort through that, I'd been stuck a lot longer

no prob. js interop is not much fun in my experience

Yeah, I'm so bad at it, but slowly getting better

👍