Clojurians Log v2
re-frame 2026-08-06
Hi. I’m just starting to learn re-frame.
The “How can I use the alpha” page at https://day8.github.io/re-frame/FAQs/alpha/ says it’s OK to use both re-frame.core and re-frame.alpha at the same time. When I do that I get a “re-frame: overwriting :error handler” warning in the console.
Is that expected?
Is it harmless?
Can I make it not appear?
More detail:
I’m using re-frame 1.4.7.
The full message is:
installHook.js:1 re-frame: overwriting :error handler for: {ns: null, name: 'event-handler', fqn: 'event-handler', _hash: -487718843, cljs$lang$protocol_mask$partition0$: 2153775105, …}
overrideMethod @ installHook.js:1
(anonymous) @ core.cljs:4096
(anonymous) @ core.cljs:4091
(anonymous) @ core.cljs:4085
(anonymous) @ core.cljs:4079
(anonymous) @ core.cljs:4073
(anonymous) @ core.cljs:4108
(anonymous) @ dev_setup.cljs:82
(anonymous) @ dev_setup.cljs:78
(anonymous) @ core.cljs:4107
(anonymous) @ loggers.cljc:39
re_frame$registrar$register_handler @ registrar.cljc:43
re_frame$alpha$reg_event_error_handler @ alpha.cljc:747
(anonymous) @ alpha.cljc:749
goog.globalEval @ main.js:451
env.evalLoad @ main.js:1408
(anonymous) @ main.js:1622
It's harmless - the error handler is identical.
Seems like it's a side-effect of an attempt to make re-frame.alpha usable without requiring re-frame.core.
Also, seems like you don't use https://github.com/binaryage/cljs-devtools - I highly recommend it. Then CLJS values reported to the JS console will be rendered properly.
OK. Good to know. And thanks for the suggestion — I’ll take a look.