@nberger @drapanjanas Hi, I found a snippet about lazy loading here: https://gist.github.com/nberger/b5e316a43ffc3b7d5e084b228bd83899. It’s not clear to me how I could use it, do you have an example of its usage?

Is there a way to stop or restart a nodejs repl session that was started via piggyback? Hoping to restart to cljs repl without restarting cider.

Is it possible to use clojurescript on static site generators like jekyll, hexo or hugo instead of javascript? I know clojurescript compiles down to javascript so does that mean I can just replace the javascript in a theme with clojurescript?

@dorianc.b yes, here is a post about one approach: https://hashrocket.com/blog/posts/the-front-end-development-environment-of-my-dreams

@isak thanks, I was thinking about picking up going to javascript but the though of going back to an imperative language but it was....difficult

@dorianc.b it’s really easy, I have a Jekyll blog where all the JS is ClojureScript

Is it possible to destructure js properties as in {:keys [a b]}?

no

maybe (let [{:strs [a b]} (js->clj o)] …) is the closest then

you can extend object type with ILookup in your application

not recommended for a library

(extend-type object ILookup (-lookup [o k] (aget o k)))

and then destructure with {:strs []}

By the way, is it possible to look up the names of defrecord fields after closure has renamed them in :advanced mode? Other than parsing them from the string representation of the constructor function?

@miikka (defrecord Thing [field]) (:field (Thing.)), keyword access always works for records

Yeah but if you need the actual names of the fields for some JavaScript interop

hmm don't think that is possible

there is some stuff in goog.reflect but I doubt that works

Oh! goog.reflect.objectProperty looks useful. Thanks for the pointer.

let me know if it works, never actually used anything other than sinkValue 😛

Well, it's a bit tricky since it takes as an argument a string literal. But I guess it'd be possible to do something nice with sufficiently advanced macro trickery.

what kind of JS interop are you doing that you are passing records into it?

maybe externs can help to prevent the rename?

I'd like to feed records to Vega (https://vega.github.io/vega/), which does string-based property access and code generation under the hood. Externs are fine for solving this, but I was thinking that maybe I could do something more automated.

@miikka pretty sure we have (.getBasis Foo) ?

but as @thheller implied, you can't use these directly, you might need to use reflect (but not sure if that’s applicable here)

you can of course use getBasis plus conversion to keyword

Yeah, getBasis gives the CLJS names of the fields and reflect would give me the renamed property names except that it takes string literals, so I can't just apply it to getBasis results at runtime

oh I missed the part about Vega

yeah dunno then

https://medium.com/@addyosmani/javascript-start-up-performance-69200f43b201#.pai9ej388 @dnolen sneaking into JS performance articles 😉

@thheller interesting though it always so annoying that these posts have the Google spin

https://arewefastyet.com/#machine=29&view=single&suite=octane&subtest=CodeLoad

I think JavaScriptCore has like 10X fewer engineers than V8

yeah but I agree with the point that benchmarks typically do not reflect real world results

real world apps usually do not do the same thing 1.000.000 times

it is nice to know though that the Closure Compiler (probably) does the most efficient thing already which we get for free

yep

does clojurescript not have extends?

it does

well, I have a cljc ns that's fine in a clojure repl, but won't compile in cljs with errors: WARNING: Use of undeclared Var myns.core/extends?

here is a solution

oh, I’m sorry, wrong channel

are you checking that an object satisfies a protocol?

yes

(satisfies? Protocol obj)

ah...

WARNING: Can't take value of macro cljs.core/satisfies?

in (cond

...maybe i should find another way altogether

When I run lein cljsbuild once, my app compiles without errors, but when I start a ClojureScript REPL using figwheel, I get this error: No such namespace: cognitect.transit, could not locate cognitect/transit.cljs, cognitect/transit.cljc, or Closure namespace "cognitect.transit". I did include [com.cognitect/transit-cljs "0.8.239"] in my project.clj. Any ideas what's going on?

I need to write something like this in ClojureScript:

<List …>

(def List* (.createFactory js/React js/ReactVirtualized.List))

(List* …)

are you using reagent?

@borkdude: have you tried [(reagent/adapt-react-class js/ReactVirtualized.List)]?

I’m trying to write this example in cljs: https://github.com/bvaughn/react-virtualized/blob/master/docs/InfiniteLoader.md#examples (search for list to see what I’m trying)

Yes, I am using reagent, but I can’t use [....] I think (just look at the example)

@borkdude: I just uploaded an example of the infinite-scroll gist in https://github.com/nberger/reagent-infinite-scroll/blob/master/src/cljs/reagent_infinite_scroll/core.cljs

borkdude: yes, you can use [...], but it requires a reagent component.

reagent/adapt-react-class adapts a react component (class) into a reagent component (function)

You could do:

(def list* (reagent/adapt-react-class js/ReactVirtualized.List))

[list*]

Also fixed a couple issues with the infinite-scroll logic itself. Use it at your own risk though 🙂

@pupeno Yes, but does that work in this example?

<InfiniteLoader
    isRowLoaded={isRowLoaded}
    loadMoreRows={loadMoreRows}
    rowCount={remoteRowCount}
  >
    {({ onRowsRendered, registerChild }) => (
      <List
        height={200}
        onRowsRendered={onRowsRendered}
        ref={registerChild}
        rowCount={list.length}
        rowHeight={20}
        rowRenderer={rowRenderer}
        width={300}
      />
    )}
  </InfiniteLoader>

The InfiniteLoader expects a function which returns a component

@nberger thanks, I’ll check it out!

(js/React.createElement List #js {} ...) is equal to jsx <List ...>

Yeah, in that case, you should just create the react element, but if you needed to pass a reagent component, you should use reagent/as-element

Hmm, with js/React.createElement js/ReactVirtualized.List, I still get the same error message

Gist: https://gist.github.com/borkdude/3c1dc22847d6b3789794c1461caf8169

Ah, the error is coming from row-renderer* now I think

uhm I don't know enough about reagent, I don't understand what all that means

but if you just do the (js/React.createElement List ...) call alone it should work?

what is :>?

just do React.createElement for that bit as well? 🙂

Got it… If I replace row-renderer with:

(defn row-renderer []
  (js/React.createElement "div" #js {} “foo”))

@thheller :> is short for adapting a reagent component to a react component

no sorry, the other way around 🙂

Someone out here who can help me with upgrading a cljsjs package? I need the checksum, but it doesn’t print it

it’s the only thing I need before committing

There are #reagent and #cljsjs channels as well.

@pupeno Thanks, I already spammed those 🙂

ha! ok.

Also solved now.

if I want to return a promise in clojurescript, can I use goog.Promise?

I guess I can just use a vanille JS one

I tend to reach for closure features because they are backwards compatible