can't say without more context. $jscomp for polyfills or other compiler generated code that is correct.

Property '$jscomp' doesn't exist when does it say that? did you check the generated source if its actually defined? just search for $jscomp= or $jscomp =? maybe it is defined just not in a way that hermes find it?

since you are using react-native doesn't metro perform the polyfilling for you? why have the CLJS do it?

Long isn't a polyfill? its just a regular closure library class so I'm not sure how this relates?

I’ve done some more digging, here’s some more info and what I’ve found so far: • The error at app runtime, even before a debugger can attach. There’s no stacktrace, just a oneline log in metro • I compared the shadow output before and after the update and did some divide and conquer and found that after the update there’s a new SHADOW_ENV.evalLoad("goog.iter.es6.js"... that wasn’t present before. Inside of it there’s a call to $jscomp.inherits(...) which seems to be the one that triggers the error in metro (confirmed by changing the code, renaming $jscomp to something else which changes the error output)

It seems that the es6 iter is required from various collection types now, i.e. from goog.structs.map which in the updated version has two new requires: goog.iter.es6 and goog.collections.iters

yes, a variety of things in the closure library got modernized and use es6 features

but $jscomp should be defined regardless. did you check if it is ever assigned anywhere?

I maybe assumed that react-native is just capable of es6+ and polyfilling isn't necessary and never handled $jscomp setup because of that

but in the other targets this is automated so should be for react-native too

might be enough to try to prepend global.$jscomp = {} to the generated output as a test

my guess is the assignment actually exists but is not exported as a global

and as such the code cannot find it

goog.base contains this

var jscomp = goog.global["$jscomp"];
  if (!jscomp) {
    goog.global["$jscomp"] = jscomp = {};
  }

no, thats not it

Adding global.$jscomp = goog did the trick.

thats not correct, it is not goog. should be {}

^^ but that would not help when the code is calling $jscomp.inherits(...)

well, I'm assuming that the polyfills are actually added to the code somewhere

goog.inherits is not what $jscomp.inherits normally would be

and most certainly goog does not contain any of the other polyfills you might need

if they aren't added anywhere else either then polyfill output is just ignored

just search for $jscomp. uses in the code. it should include some assignments not just uses

feel free to open an issue about this, cannot look into it right now myself

This is the compiled goog.iter.es6 -> https://gist.github.com/stigi/2ac4488602b52552998fbaf74f92d28f As far as I can tell the $jscomp.inherits call is part of the extend from the https://github.com/google/closure-library/blob/99a2e56fd143a71ad16381c12017e53989e84b28/closure/goog/iter/es6.js#L116.

Thanks for your help already @U05224H0W. I’ll dig some more.

It seems to occur everywhere where a ES6 class is with extend is compiled with ES5 output format. Trying to come up with a small repro.

I think you can stop your investigation. I think I just assumed that react-native was capable of es6+ and never bothered to include any polyfill code at all

busy with other stuff so can't look at it right now

@U05224H0W it actually reproduces in browser trargets as well. Trying shadow vs standard CLJS compiler now and will provide a small repro.

Reproduced the issue with standard clojurescript compiler in node env. Here’s a tiny repo with a demo https://github.com/stigi/clojurescript-es5-issue

this doesn't mean anything for shadow-cljs though

it handles all of this on its own and doesn't use anything from the regular CLJS tools

Updated the repo with shadow reproduction steps. Not sure on which project to open an issue now. My guess would be https://github.com/google/closure-compiler then.

well for shadow-cljs in the shadow-cljs repo

it might be an issue in the closure compiler but I'd want to confirm that on the shadow-cljs side first

there was a closure compiler issue before where it didn't properly keep track of which polyfills were added and rewrote but didn't add polyfills

We also stumbled across this https://github.com/google/closure-compiler/issues/3879#issuecomment-948583193 that I’m working my way through right now.

https://github.com/google/closure-compiler/issues/3890

FYI: compiler option :force-library-injection #{"es6/util/inherits"} did the trick.

Shall I open a PR adding that one to the list of existing polyfills here? https://github.com/thheller/shadow-cljs/blob/d6e14905022b719d2e240646417f53d9ee452e4d/src/main/shadow/build/closure.clj#L2568-L2585