Using eval from cljs.js with webpack

Question

In clojurescript 1.10.773 it is impossible to use eval from cljs.js when I've bundled the project with webpack I think this is because eval is calling find-ns-obj, when doesn't work with the :bundle :target. That makes sense, but this error still occurs when an :ns is passed in the options map.

Using eval from cljs.js used to work in clojurescript 1.10.741, even when :target was set to :bundle. It looks like this is because previous versions of clojurescript never set *target* when it was set in the compiler options.

The error I'm getting is:

core.cljs:11642 Uncaught Error: find-ns-obj not supported for target bundle
    at Object.cljs$core$find_ns_obj [as find_ns_obj] (core.cljs:11642)
    at Function.cljs$core$IFn$_invoke$arity$1 (core.cljs:11660)
    at cljs$core$create_ns (core.cljs:11657)
    at Function.cljs$js$compile_str_STAR__$_compile_loop (js.cljs:918)
    at Function.cljs$core$IFn$_invoke$arity$3 (core.cljs:3918)
    at Function.cljs$core$IFn$_invoke$arity$2 (core.cljs:3913)
    at Function.cljs$core$IFn$_invoke$arity$2 (core.cljs:3948)
    at core.cljs:10831
    at Function.cljs$core$IFn$_invoke$arity$1 (core.cljs:10826)
    at Function.cljs$core$IFn$_invoke$arity$variadic (core.cljs:10831)
cljs$core$find_ns_obj @ core.cljs:11642
(anonymous) @ core.cljs:11660
cljs$core$create_ns @ core.cljs:11657
cljs$js$compile_str_STAR__$_compile_loop @ js.cljs:918
(anonymous) @ core.cljs:3918
(anonymous) @ core.cljs:3913
(anonymous) @ core.cljs:3948
(anonymous) @ core.cljs:10831
(anonymous) @ core.cljs:10826
(anonymous) @ core.cljs:10831
cljs$core$trampoline @ core.cljs:10817
cljs$js$compile_str_STAR_ @ js.cljs:910
(anonymous) @ js.cljs:1019
cljs$js$compile_str @ js.cljs:968
interactive_syntax$core$eval_str @ core.cljs:48
run @ core.cljs:351
callCallback @ react-dom.development.js:188
invokeGuardedCallbackDev @ react-dom.development.js:237
invokeGuardedCallback @ react-dom.development.js:292
invokeGuardedCallbackAndCatchFirstError @ react-dom.development.js:306
executeDispatch @ react-dom.development.js:389
executeDispatchesInOrder @ react-dom.development.js:414
executeDispatchesAndRelease @ react-dom.development.js:3278
executeDispatchesAndReleaseTopLevel @ react-dom.development.js:3287
forEachAccumulated @ react-dom.development.js:3259
runEventsInBatch @ react-dom.development.js:3304
runExtractedPluginEventsInBatch @ react-dom.development.js:3514
handleTopLevel @ react-dom.development.js:3558
batchedEventUpdates$1 @ react-dom.development.js:21871
batchedEventUpdates @ react-dom.development.js:795
dispatchEventForLegacyPluginEventSystem @ react-dom.development.js:3568
attemptToDispatchEvent @ react-dom.development.js:4267
dispatchEvent @ react-dom.development.js:4189
unstable_runWithPriority @ scheduler.development.js:653
runWithPriority$1 @ react-dom.development.js:11039
discreteUpdates$1 @ react-dom.development.js:21887
discreteUpdates @ react-dom.development.js:806
dispatchDiscreteEvent @ react-dom.development.js:4168
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react-dom.development.js:327 Uncaught Error: find-ns-obj not supported for target bundle
    at Object.cljs$core$find_ns_obj [as find_ns_obj] (core.cljs:11642)
    at Function.cljs$core$IFn$_invoke$arity$1 (core.cljs:11660)
    at cljs$core$create_ns (core.cljs:11657)
    at Function.cljs$js$compile_str_STAR__$_compile_loop (js.cljs:918)
    at Function.cljs$core$IFn$_invoke$arity$3 (core.cljs:3918)
    at Function.cljs$core$IFn$_invoke$arity$2 (core.cljs:3913)
    at Function.cljs$core$IFn$_invoke$arity$2 (core.cljs:3948)
    at core.cljs:10831
    at Function.cljs$core$IFn$_invoke$arity$1 (core.cljs:10826)
    at Function.cljs$core$IFn$_invoke$arity$variadic (core.cljs:10831)

Any use of eval, or eval-str, compile-str, etc. gives it to me. Say:

(eval-str (empty-state) "(+ 1 2)" "UNTITLED" {:eval js-eval} println)

And I get this error even if I provide my own :ns.

Answer 1

I would add that you'll probably have more luck by adding https://github.com/borkdude/sci instead of using ClojureScript's eval.

Comments

Unfortunately SCI doesn't have a function like `compile-str` from cljs.js (at least not in the api docs), so it seems impossible to pass the compiled results to something like Stopify (https://www.stopify.org/) to 'pause' a running program.

So unless I can pause/resume code running with SCI, or at the very least run potentially infinite loops without completely locking up the GUI, its kind of a non-starter.

Answer 2

self-hosted//bootstrapped cljs is a hard trick

You may not use advanced compilation, and enable/disable some other build flags.

https://blog.klipse.tech/clojurescript/2016/04/04/self-host-part-1.html

https://code.thheller.com/blog/shadow-cljs/2017/10/14/bootstrap-support.html

Comments

Also, checkout clojurians.net and the #shadow-cljs channel.