Clojurians Log v2

@dpsutton thanks for your reply Ah I see, in Javascript I can just

let isclicked = false
false
isclicked = !isclicked
true
isclicked
true
isclicked = !isclicked
false
isclicked
false

yes. in your example you can do (swap! isclicked not)

user=> (def clicked? (atom false))
#'user/clicked?
user=> (swap! clicked? not)
true
user=> @clicked?
true
user=>

if you just want to set the value of an atom irrespective of its current value then (reset! clicked? true) or (reset! clicked? (not @clicked?)) . note this one where you are setting its value based on the current value of the atom is precisely what (swap! clicked? not) is doing except its changing it atomically without race conditions

ohhhhh that makes sense, thanks so much @dpsutton time and help

for sure!

Hey, I'd like to do (.addEventListener js/document "mousemove" handler) but on a specific element. What's the idiomatic way of doing this in reagent? Using react refs?

Hello, how to deal with tag object such as data and time in cljs, sent from clj? Thanks.

got an example?

For example, this edn from clojure to cljs, will not be read by cljs: (str {:A (java-time.local/local-date)}) ;; => "{:A #object[java.time.LocalDate 0x371f749c \"2020-12-11\"]}"

correct because it hasn't been serialized in a way that it can be. "{:A #object[java.time.LocalDate 0x371f749c \"2020-12-11\"]}" isn't a readable string. So there's no chance of cljs handling it.

but you can't send an arbitrary java object (or a string representation of one) over to the browser

you can str it to get a nice format that you can reconstitute into a date on the cljs side. if you have timezone information you can use that to get a java.util.Date which has reproducibility between clj and cljs. You could also see how that is accomplished to achieve something similar

Thank you. Then to deal with data and time, I should convert these into string representation before transmit between server and client.

you're most probably using json or edn (or transit). all of these are string representations. that's kind of the name of the game

events are typically added via the attrs map passed in as the second element of a reagent component vector. e.g. [:div {:on-mouse-move my-handler} "div content"]

thanks @dane.email, but is that the case for on-move too? I get Unknown event handler property onMove if I try to use it as a map

never mind, its' called on-mouse-move!

haha you had me doubting myself, was just pulling up a project to try it out

glad you figured it out !

Has anyone seen this error when using this unicode matching regex and compiling a prod build (optimizations advanced): (re-seq #"(?u)\p{L}\p{L}\p{L}+" input-string)

ERROR: JSC_UNTRANSPILABLE. Cannot convert ECMASCRIPT_2018 feature "RegExp unicode property escape" to targeted output language.

In a reagent application, I have some code along the lines of:

(r/with-let [pointer (r/atom nil)
               handler #(let [rect (.. % -target getBoundingClientRect)]
                          (swap! pointer assoc
                                 :x (- (.-clientX %) (.-left rect))
                                 :y (- (.-clientY %) (.-top rect))))]
   widget

https://soundcloud.com/user-959992602/followers we need more clojurescript podcast followers. awesome content

asking again, hopefully with a better question: how can I capture a piece of the dom (in my case an svg element) so that I can refer to it in something like (let [rect (.. MY_ELEMENT -target getBoundingClientRect)] ...) ?

https://google.github.io/closure-library/api/goog.dom.html has a helpful findElement function

Just in case - if you're using React, use refs.

thanks! @dpsutton and @p-himik! I think I could have an XY problem right here so let's consider concretely:

(defn drawer-ui []
  (r/with-let [pointer (r/atom nil)
               handler #(let [rect (.. % -target getBoundingClientRect)]
                          (swap! pointer assoc
                                 :x (- (.-clientX %) (.-left rect))
                                 :y (- (.-clientY %) (.-top rect))))]
    [:div
     [:svg  {:on-mouse-move handler}
      ...]]))

put a ref function on the svg to reset an atom to the argument passed in to that function and use the value of that atom as the svg

^ that. Or just react/createRef if you prefer React API to atoms.

First and foremost, read the documentation on refs. There might be some surprises that aren't fun to debug.

and its sensitive to inline functions that are recreated on every render versus defined functions

thanks, I'll dig into that!

Does anyone use Tupelo? I'm getting compile errors, like this one where it does seem to be wrong based on MapEntry documentation. ------ WARNING #1 - :fn-arity -------------------------------------------------- Resource: tupelo/core.cljc:1208:12 -------------------------------------------------------------------------------- 1205 | "Returns a clojure.lang.MapEntry constructed from the given key and val" 1206 | [key val] 1207 | #?(:clj (clojure.lang.MapEntry/create key val) 1208 | :cljs (cljs.core.MapEntry. key val))) ------------------^------------------------------------------------------------- Wrong number of args (2) passed to cljs.core.MapEntry

there seems to be a jira issue somewhat related to this: https://clojure.atlassian.net/browse/CLJS-2982

https://github.com/cloojure/tupelo/issues/17

not related to that jira issue i don't believe. its just wrong

Yes I did notice the issues in Jira and Git around the use of MapEntry. Given that the Tupelo code is incorrect, I wonder if anyone is using it with Clojurescript. For me, the Tupelo compile is failing so it's not something I can fix in my code. I've tried the latest version as well as an older version. I just wanted to use their unsigned-byte->hexfunction. Any suggestions for a simple function to convert a js/Uint8Array into a string of hexidecimal characters?

i'm suprised the compilation is failing unless you have warnings set to throw errors

you could just grab the source with attribution

https://github.com/cloojure/tupelo/blob/master/src/cljc/tupelo/misc.cljc#L127-L147

Yes, you are correct that they are warnings. So I guess I should ignore them, though that seems like a bad practice. Cut and paste the code works for me since it is such a simple function (yeah I could have written it myself but Tupelo had already done it. sigh).

Thanks for your help and quick response. This is a great channel!!!

submit a patch. i believe you can just add a nil as the third argument. its a hash which can be nil signalling it needs to be computed (i think. going off memory)

There was a second warning for an undeclared variable. I get nervous when my code has these warnings, let alone use a library that has them. While these two warnings are unrelated to the function I want to use, just seems like bad hygiene. ------ WARNING #2 - :undeclared-var -------------------------------------------- Resource: tupelo/core.cljc:1395:46 -------------------------------------------------------------------------------- 1392 | ;----------------------------------------------------------------------------- 1393 | (s/defn cum-vector-append :- s/Any ; #todo file bug report for CLJS 1394 | "Works inside of a with-cum-vector block to append a new vector value." 1395 | [value :- s/Any] (cum-val-set-it (append it value))) ; #todo copy td/cum-vector-swap-append kludge ----------------------------------------------------^--------------------------- Use of undeclared Var tupelo.core/it

based on these warnings i wouldn't use this library

Does heavy use of core.async have a big affect on the output during advanced mode?