try adding this line to your .emacs (setq cider-repl-use-pretty-printing t)

Is there a way to remove the namespace prefix from all the keys in a map? I’d like to json-stringify a map and send it over the wire w/o the ns

@titanroark If you just call name on those keys, you'll get strings without the namespace prefix.

There are a few walk-related functions in the Clojure library that can make that easier if it's a nested map. Or just use org.clojure/data.json (or Cheshire or jsonista) to turn it into actual JSON, which should all lose the namespace prefix, or can be configured to do so.

dev=> (require '[clojure.data.json :as json])
nil
dev=> (json/write-str {:foo/bar 1 :bar/quux "two"})
"{\"bar\":1,\"quux\":\"two\"}"

https://github.com/clojure/data.json for more details.

Hi I have the following reitit endpoint in my server:

["/organizations/:id/users/:uid"
     {:put {:summary ""
            :parameters {:role string?}
            :responses {200 {:body map?}
                        500 {:body string?}}
            :handler foo}}]

{:http-xhrio {:method          :put
                            :uri             (str "/organizations/" (get user "organization-id") "/users/" (get user "id"))
                            :params          {:role role}
                            :format          (ajax/json-request-format)
                            :response-format (ajax/json-response-format {:keywords true?})
                            :on-success      [:block-editing/handle-success]
                            :on-failure      [:block-editing/handle-error]}

xhrio.js:645 PUT  404 (Not Found)

In core.async is there an opposite to "onto-chan" that returns a collection of the items in a channel? Is there a better alternative?

I am writing out some data into an edn file I can see in the file its tagged like this :created #time/instant "2021-10-23T19:25:46.574852Z", how ever when I read it back in using slurp and read-string I get this :created (. java.time.Instant parse "2021-10-21T11:54:31.831771Z") this is causing my code to fail when I call things like tick/year I get an IExtraction error I would have expected the read edn to match the initial tag of #time/instant so bit baffled as to whats happening, any one able to point me in the right direction ?

never mind combination of things using the wrong read-string, and then needing to add my own reader for the tag

How do you pass arguments in double dot notation ((.. fs -promises readFile) "db.edn") or (.. fs -promises readFile "db.edn") P.S. - doesn't work with either of them This worked - (.readFile (.-promises fs) "db.edn")

(get-in m  [:a :b])
  (-> m :a :b)

imho, a matter of preference, although with the get-in variant, you can have a default value if not found.

I've seen get-in used more often, but I think it's very preference/context dependant.

(I use both variants)

i’ve seen a good argument (i think from zach tellman) that you should always prefer to use the functions that most concretely represent the type. I need to go look it up. But i thought it was a useful guideline

get-in is more dynamic, e.g. the list of keys does not need to be a compile time constant

get-in also works for other kinds of keys

-> is likely going to be faster (constant fixed set of keys, for certain things keyword look up calls turn into field accesses), but maybe not by enough to care about, -> allows for more complicated processes because you can stick random functions in there

-> is I think definitely faster right now (but that may not always be the case in the future)

that is surprising to me. i would have guessed get-in would be faster, kinda specialized to key value lookup

I mean, -> expands into a fixed set of function calls, get-in is a loop over the contents of a vector

by fixed I mean statically known at compile time

user=> (dotimes [_ 10] (time (dotimes [_ 100000] (-> m :a :b))))
"Elapsed time: 5.769764 msecs"
"Elapsed time: 2.083059 msecs"
"Elapsed time: 2.065704 msecs"
"Elapsed time: 2.026249 msecs"
"Elapsed time: 1.989106 msecs"
"Elapsed time: 1.969671 msecs"
"Elapsed time: 1.446167 msecs"
"Elapsed time: 1.416666 msecs"
"Elapsed time: 1.408738 msecs"
"Elapsed time: 1.409222 msecs"
nil
user=> (dotimes [_ 10] (time (dotimes [_ 100000] (get-in m [:a :b]))))
"Elapsed time: 21.282209 msecs"
"Elapsed time: 15.645264 msecs"
"Elapsed time: 13.058268 msecs"
"Elapsed time: 12.87428 msecs"
"Elapsed time: 7.01354 msecs"
"Elapsed time: 6.806815 msecs"
"Elapsed time: 6.66232 msecs"
"Elapsed time: 6.803173 msecs"
"Elapsed time: 18.48002 msecs"
"Elapsed time: 5.500962 msecs"
nil

easy to test

good points. makes sense

in opposition to the argument above, I think there is actually an argument to rely on as few assumptions about type as possible

Damn, you beat me to it

lookup is more generic than maps

lambda the ultimate

but as I said, get-in could be, and should be, faster than it is so don't carry this performance comparison as absolute

I use both -> and get-in in these cases and choose primarily on which one is easier to understand in the context of the code

the perf argument is weak, unless you're in a very hot path here (like the page router of your web app)

and even in that case, hotspot in a new jvm might make the above a wash

in fact, that was java 8 above, here's java 17

user=> (dotimes [_ 10] (time (dotimes [_ 100000] (-> m :a :b))))
"Elapsed time: 11.085806 msecs"
"Elapsed time: 5.569733 msecs"
"Elapsed time: 5.167711 msecs"
"Elapsed time: 5.269218 msecs"
"Elapsed time: 5.093628 msecs"
"Elapsed time: 5.052448 msecs"
"Elapsed time: 5.143588 msecs"
"Elapsed time: 2.802478 msecs"
"Elapsed time: 1.395313 msecs"
"Elapsed time: 1.411534 msecs"
nil
user=> (dotimes [_ 10] (time (dotimes [_ 100000] (get-in m [:a :b]))))
"Elapsed time: 21.824148 msecs"
"Elapsed time: 17.589059 msecs"
"Elapsed time: 13.940786 msecs"
"Elapsed time: 13.9655 msecs"
"Elapsed time: 3.989803 msecs"
"Elapsed time: 4.947388 msecs"
"Elapsed time: 4.247937 msecs"
"Elapsed time: 3.350112 msecs"
"Elapsed time: 4.805961 msecs"
"Elapsed time: 6.8933 msecs"

(defn has-keys? [m keys]
  (apply = (map count [keys (select-keys m keys)])))

Hello friends! I'm trying something here: I have a project that I'm starting off with clojure and I'll be deploying it on aws batch. This means this is going to be shipper as an docker image. For testing I would like to run tests and, some things, in docker. Also I don't want to miss on Calva. The tricky part is about environment variables. I configured environ and I have correctly set up the profiles, so locally, calva works just fine. However, for docker/docker-cmpose I'm using .env as a way of configuring the environment variables for the image. Is there a lean way of writing this only once and having access to the best of both worlds? Or should I just open up the REPL server in docker and allow calva to connect to it?

Hi. I've decided to start thoroughly studying the clojure standard library. Thus I'm looking for advice on how to approach it. Which resources did you use/are you using for this purpose? I'm thinking I should just read clojure-docs, source code and usage examples for every core function. Do you think there is a better way? Any resources that are worth noting? I came across "Clojure the essential reference", but wasn't able to find a free copy anywhere, so it's not really an option for me.