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missionary 2026-01-21
Hi I started to rewrite an old JS app to ClojureScript and I use missionary to handle the async part. I'm wondering if this code is ok:
;; NodeJS server
(def app (express))
;; Main task
(defn ?do-something
[req]
(m/sp ...))
(.get app "/" (fn [req res)
((?do-something req)
(fn [ok] (.send res ok))
(fn [error] ...)))
Hendrik 2026-01-21T09:21:33.607499Z
Your code looks ok. Just pay attention, that you do not run blocking functions inside the tasks. use m/via
for blocking stuff (jvm only).
m/via works on NodeJS?
Hendrik 2026-01-21T09:29:16.601059Z
oh. I did not read your message carefully enough. No it does not. via-call will throw.
Hendrik 2026-01-21T09:30:20.148259Z
however, I guess, that there shouldn’t be to many blocking apis on NodeJS. if there are any at all. So it should not be a problem.
xificurC 2026-01-21T09:45:38.075309Z
the idea is to compose async stuff as tasks/flows to benefit from the library's supervision. Ideally one ends up with a single task at the root of the application. Then yes, one has to initiate the root task as (root-task s f)
leonoel 2026-01-21T16:38:30.888419Z
this pattern is fine, but make sure the callbacks never throw
Ok. Thanks guys!