This wouldn't work in CLJ either. When you wrap a symbol in [], that symbol no longer exists within [] - only its value does. In order for #'... or (var ...) to work, they have to receive the symbol itself, at compile time. CLJ has run time capabilities for that where you can get a var from a namespace by its name as a string. But CLJS does not - you have to create your own dictionary of names to values and use that.

Okay good to know! At this point I will say or I use ns-interns and check the type of every value or I can transform required-fields in a big ratom and simply use keys on it

Note that in CLJS ns-interns is a macro that has to receive a symbol, so stuff like *ns* won't work there.

actually optional is for data that can be or not there, exception is for flow that will fail (eventually), they seems like different concepts to me…

i've been out of the node.js world for awhile. prior i would probably just use something like sqlite or redis

i think there are a couple cljs dbs that persist to local storage or something. maybe you could use some duct tape and wire to get those to persist to some durable storage in node.js

but sqlite is hard to beat

I ended up using Google sheets lol

Kind of not what I would have expected as an answer to my question but in the context of what I’m working on I think it makes sense

nice!

@U04V15CAJ what do you mean by pre-require?

e.g. for clojure spec alpha, the user has to require clojure.test.check first to use certain features. https://github.com/clojure/clojurescript/blob/6443518850d8e4f1e09be99d4669e8d4a5e893a3/src/main/cljs/cljs/spec/test/alpha.cljc#L258

@U04V15CAJ ah yeah, thats clever, since js doesn’t really care. the two problems are: shadow + clj-kondo really like warning me now, but i guess i’ll find a way to make them stop

can you give an example of what clj-kondo "complains" about?

(def debux-enabled?
     (try
       (when (exists? debux.common.util/result*)
         true)
       (catch :default _ false)))

(if debux-enabled? debux.common.util/result* [])

clj-kondo should support this:

$ clj-kondo --lint - --lang cljs <<< '(exists? foo.bar/az)'
<stdin>:1:10: warning: Unresolved namespace foo.bar. Are you missing a require?

I'll fix it on the next release

for now you can put #_:clj-kondo/ignore in front of the offending symbol

i guess i could use a macro to only spit out the debux version if the clj version of the require also exists, but that seems like overkill

i’ll make an issue and try to get shadow to not be pissed at me. thanks for the help!

ah btw i have the same clj-kondo problem in clj, do you want it in the same issue?

(def debux-enabled?
     (try
       (require 'debux.common.util)
       (when debux.common.util/result*
         true)
       (catch Throwable _ false)))

clojure does not support the above I think

does it?

are you sure? seems to work for me or at least it compiles

ill run it, let me check

works in the repl

i’ve stolen the concept from here: https://github.com/dakrone/clj-http/blob/3.x/src/clj_http/client.clj

try it in in a standalone file

and then run it from the command line

it will fail

you cannot use a fully qualified symbol like that. clj-http doesn't do that

ah so you mean the require will work but the usage will fail? that makes sense

yeah

mhh, seems like a lot of work wrap everything with resolves

https://github.com/borkdude/dynaload

you only have to wrap it once and then call the wrapper

@U04V15CAJ that’s great, thanks so much!

may I suggest flipping the entire exists logic? ie. instead of checking if something exists you have that something register itself on load

so you have (ns your.lib.registry) with (defn register-thing [whatever] ...)

and the "conditionally loaded" thing just registers itself when loaded

at runtime you can just check if the thing did register itself without mucking arround in global namespaces and such?

You can do that if you control the optional namespace

you can by just creating an extra namespace that bridges it 😉

unless my brain is foggy because I just woke up, but wouldn’t I have the same “optional” problem in the other direction now?

I made a gist for this basic idea a while ago https://gist.github.com/thheller/fa044450a6470fdd1afdbcf3f37a65e3

point is you have a (some-ns/do-something) function somewhere that you call

and it does something different depending on whether a thing registered itself or not

but it only checks its own registry and not some namespaces and such

given that namespaces don't really exist in CLJS anything related to them is icky to say the least

Yeah you can make another optional namespace that you do control and then register something.

if its about debugging and stuff :preloads is usually the place where you want to load "optional" stuff

ah ok yeah I get your method. that’s how I’d do it if I had a DI container in a different language. my problem is that the optional lib doesn’t know anything about the main lib, so to do the registration i’d still have to do some magic

but yeah the final interface would be a little less magic, so thats good at least

no magic needed really since that "adapter" namespace you create can just do whatever and doesn't need to worry about anything conditional

the only problem really with all of this is :advanced not being able to detect if the conditional thing is actually loaded or not. so the calls to anything optional are not removed as they are not DCE

but there really is no easy way to solve this

well, i still need a way to know if i want to load your “browser” or the “react-native” ns if we are talking about your gist

that is handled by the build config

and i’m fine with breaking advanced compile, it’s a dev time lib anyway

ie. the :browser build obviously doesn't load the :react-native ns

no I mean say you write a logging lib of some sort

so you have (that-ns/log :something {:foo "bar"}) or so everywhere in your code

but the conditional thing is not loaded so log doesn't do anything and is technically dead code

DCE :advanced cannot detect that so it remains intact

well yeah, but that would be pretty tiny + a wasted call to a no op

but is there no decent way to detect if i should do :browser or :react without a config file? that’s what i was trying to avoid

don't know what you are trying to do exactly so can't say much more. conditional require in CLJS is not an option like it is in CLJ

thank you anyway! don’t want to waste too much more of your time, so ill play around with it more by myself for some time. if it’s ok I’ll check back in with the final result to see if I did anything too awful ;)