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#clojurescript
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2020-03-18
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Chris McCormick03:03:51

on the topic of small compile sizes - i've done some experimentation before and found that not using datastructures was a good way to keep the size small (like what @dnolen said). i wonder if there is any way to ask cljs to default to native JS datastructures such that when i ask for {} i get an object instead of a clojure hash-map?

Chris McCormick03:03:10

i know ther eis the #js reader macro which is super handy but can get a bit long winded and easy to forget

Chris McCormick03:03:25

so i'm thinking a sort of "close to js" mode where you can write clojurescript more like e.g. Wisp

lilactown03:03:08

i wish there was some way of optimizing it like that

lilactown03:03:43

it’s difficult because if you’re doing immutable updates to an object, at some point it becomes more performant to use actual mutable data structures

lilactown03:03:23

but a lot of objects live for a short time and then are discarded, in which case using a JS object would be far more performant - for code size and runtime

lilactown03:03:57

you also run into really difficult issues with equality if you do this, I’m not sure it can be done

Chris McCormick04:03:47

a thing i got working is writing clojurescript in a way that i know will compile with Wisp and then doing that at the final stage. problem is you have to use a ton of js shims for things like assoc. it's very messy but you can get very tiny artifact sizes.

Chris McCormick04:03:55

i should finish the half-written blog post I have about this

Chris McCormick04:03:30

it's only really useful if your code is very simple and what you are trying to do is very simple (like update a few divs on a page or attach a couple of event handlers)

hindol07:03:15

Not able to refer to js/Buffer. Getting Uncaught ReferenceError: Buffer is not defined. Any ideas?

(.from js/Buffer "0xf87ea00000000000000000000000000000000000000000000000000000000000000000f85494ca6e9704586eb1fb38194308e2192e43b1e1979c94ce2276efc33fee3c321e634eac28a9476e53b71c94f466a7174230056004d11178d2647c12740fa58b94b83820d6cf4b7e5aa67a2b57969caa5cdf6dff49808400000000c0")

p-himik08:03:24

Browser or Node?

p-himik08:03:48

And what version?

hindol08:03:47

Browser. I saw some examples online and it seemed it works in browser too.

p-himik08:03:36

I don't think browsers have Buffer.

p-himik08:03:26

That is, if you really need Buffer and not something like ArrayBuffer.

👍 4
hindol08:03:44

Thanks for the info. Really helpful. For now, I found I can simply pass a string to the other library instead of constructing a buffer myself.

Ben Hammond11:03:32

what is the difference between

#js{:a :b}
and
(clj->js {:a :b})
?

Ben Hammond11:03:23

my use case is that

(clj->js {:root {:flexGrow 1
                       :title {:flexGrow 1}
                       :background theme.background}})
works as expected, whereas
#js {:root {:flexGrow 1
                       :title {:flexGrow 1}
                       :background theme.background}}
does not

roman01la11:03:45

@U793EL04V the nested map should be tagged with #js as well

👍 4
roman01la11:03:25

clj->js is runtime transformation, tagged literal emits JS object directly

Ben Hammond11:03:52

so if I go down the clj->js route I should probably memoize the result

Ben Hammond11:03:23

this a MaterialUI themed style so it won't change during the session

roman01la11:03:11

yeah, there are also more subtle issues with clj->js, but I don't know all of them

roman01la11:03:34

I'd suggest to go with #js if it's a static literal

👍 4
jjttjj12:03:31

I got cljs.js/eval-str working! 🙂 This seems like strange behavior though, is this a bug? It seems like string results need to have pr-str called on them

(defn eval-str1 [s]
  (cljs/eval-str compile-state-ref s (gensym)
                 {:eval cljs/js-eval}
                 #(println "eval result:" %)))

(eval-str1 "(str \"asdf\")")
;;eval result: {:ns cljs.user, :value nil}

;;string results need to be pr-str'd?

(eval-str "(pr-str \"asdf\")") 
;;eval result: {:ns cljs.user, :value "asdf"}

(eval-str "(conj [1 2 3] 4)") ;;works
;;eval result: {:ns cljs.user, :value [1 2 3 4]}

Brandon Olivier20:03:13

What are some practical differences when working with reagent vs rum?

souenzzo22:03:12

reagent only wrap react. You manage all state yourself (and reagent will rerender) rum will tell you a "discipline" about how to manage state. @brandon149