Add ability to pass options to addEventListener in from-event

src/beicon/v2/core.cljs

@@ -129,9 +129,13 @@
                (fn [] (remove-watch atm key)))))))
 
 (defn from-event
-  "Creates an Observable by attaching an event listener to an event target"
-  [et ev]
-  (rx/fromEvent et ev))
+  "Creates an Observable by attaching an event listener to an event target
+   Args:
+      et:   the event target (e.g., a DOM element or window)
+      ev:   the event type (e.g., 'click', 'mousemove')
+      opts: optional options for the event listener (e.g., {passive: true})"
+  ([et ev & [opts]]
+   (rx/fromEvent et ev (clj->js (or opts {})))))
 
 (def ^function timer
   "Returns an observable sequence that produces a value after

test/beicon/tests/v2_test.cljs

@@ -89,6 +89,18 @@
                            (t/is (= % ["once"]))
                            (done)))))))
 
+(t/deftest observable-from-event-args
+  (t/async done
+    (let [target #js {:addEventListener (fn [type listener opts]
+                                           (t/is (= type "poked"))
+                                           (listener (.-passive opts)))
+                      :removeEventListener #()}
+          s (rx/from-event target "poked" {:passive false})]
+      (t/is (rx/observable? s))
+      (rx/end! (drain! s #(do
+                           (t/is (= % [false]))
+                           (done)))))))
+
 (t/deftest observable-with-timeout
   (t/async done
     (let [s (->> (rx/timer 200)