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Separate iterate-cursor and transduce-cursor

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arne 2025-11-22 00:10:31 +01:00
commit 97965ce8b0
1 changed files with 16 additions and 12 deletions
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22
src/computersandblues/lodestone/database.cljs
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@ -131,6 +131,14 @@
(js/console.log :logging args) (js/console.log :logging args)
(apply f args))))) (apply f args)))))
(defn iterate-cursor [f cursor-req]
(.addEventListener cursor-req "success"
(fn [ev]
(if-let [cursor (-> ev .-target .-result)]
(do (f cursor)
(.continue cursor))
(f)))))
(defn transduce-cursor (defn transduce-cursor
"Allows to transduce over all values in a cursor. "Allows to transduce over all values in a cursor.
@ -148,18 +156,14 @@
xform (xform rf)] xform (xform rf)]
(js/Promise. (js/Promise.
(fn [resolve _] (fn [resolve _]
(.addEventListener cursor-req "success" (iterate-cursor (fn [cursor]
(fn [ev] (if cursor
(if-let [cursor (-> ev .-target .-result)]
; NOTE: each step will work with the raw js value
; to avoid unnecessary conversion costs.
(let [step (xform @result (.-value cursor))] (let [step (xform @result (.-value cursor))]
(if (reduced? step) (if (reduced? step)
(resolve @step) (resolve @step)
(do (vreset! result step)))
(vreset! result step) (resolve @result)))
(.continue cursor)))) cursor-req))))))
(resolve @result)))))))))
(defn first-result (defn first-result
"Given a cursor, will return a promise that resolves to the first result. "Given a cursor, will return a promise that resolves to the first result.