hi hi, I am looking for a little help, I have a build with :target :node-library and I want to use js/performance.now which is a browser global, available with const { performance } = require('perf_hooks'); on node. see this https://stackoverflow.com/questions/23003252/window-performance-now-equivalent-in-nodejs ... Is there an easy way to get this work, I am hacking with someone elses code, so I am mostly in the dark with clojure tbh. I tried (:require ["perf_hooks" :refer (performance)] ) but that was giving me "Use of undeclared Var performance/now" I am stuck :|

@exrhizo with :refer you'd do (.now performance), :refer does not set up a namespace alias so performance/ doesn't work. you can do (:require ["perf_hooks$performance" :as perf]) and then (perf/now).

When I eval something in the REPL, I get an error that looks like this:

:repl/exception!
; 
; Execution error (TypeError) at (<cljs repl>:1).
Cannot read properties of null (reading 'cljs$core$IFn$_invoke$arity$1')

this usually means you are doing something like (foo 1 2 3) when foo is nil

yeah, but is there any way of figuring out which "foo" it is? 😄

well you are calling the code?

(defn calls-nil [f] (f 1 2 3 4 5))
(calls-nil nil)

:repl/exception!
; 
; Execution error (TypeError) at (<cljs repl>:1).
Cannot read properties of null (reading 'call')

well that is sort of an artifact of how the code is generated differently when eval'd in the REPL.

it is the basically same error though

if this is in Calva it might also be dropping some additional information

emacs also seems to be doing that

(not on this example, but make sure to look at the server log in case there is any)

if, for example, I set the :init-fn to calls-nil, I get proper traces in the browser console:

but if I eval from Calva, nothing gets printed to the browser console

nothing in the shadow-cljs terminal log either :thinking_face:

well you can get that via (.-stack *e) after the errors

(js/console.log *e) would give you the above too I guess

nice, thanks! the second one is great, the first one isn't sourcemapped

yeah source mapping is the problem. didn't write that yet for the errors

is this something that could be fixed on Calva's side?

no

@thheller hmm, any other way of getting the sourcemapped trace from *e , or is it only possible by js/console.log ing it?

would have been cool to be able to see/click the sourcemapped error without needing to switch to the browser window

well you can implement it 😉

in case of console.log the browser does it for us

I haven't found a way to make it do that in userland code

I'll give it a shot and report findings if I manage to do anything 😄 Thanks for shadow-cljs by the way, it's a great project

https://github.com/thheller/shadow-cljs/blob/b8466f176b6e8f6bf61cd70fbfbaf4762c581eb1/src/main/shadow/remote/runtime/obj_support.cljc#L100

thats where the string for the error is generated

that is just calling https://github.com/clojure/clojurescript/blob/95c5cf384a128503b072b7b1916af1a1d5c8871c/src/main/cljs/cljs/repl.cljs#L229

by all means feel free to change either place and make it better 😉

awesome, thanks!