From a4dd7e4e9c98fad629430b40a1b2f07af8ce41db Mon Sep 17 00:00:00 2001
From: Nick Alexander <nalexander@mozilla.com>
Date: Thu, 13 Oct 2016 14:28:23 -0700
Subject: [PATCH] Review comment: make a large-ish dropping buffer for JS
 listen! consumers.

---
 src/common/datomish/transact.cljc | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/common/datomish/transact.cljc b/src/common/datomish/transact.cljc
index 3c369ba7..81daefc8 100644
--- a/src/common/datomish/transact.cljc
+++ b/src/common/datomish/transact.cljc
@@ -648,8 +648,9 @@
   (a/tap (:listener-mult conn) listener-sink)
   listener-sink)
 
-(defn- -listen-chan [f]
-  (let [c (a/chan (a/sliding-buffer 10))]
+(defn- -listen-chan
+  [f n]
+  (let [c (a/chan (a/dropping-buffer n))]
     (go-loop []
       (when-let [v (<! c)]
         (do
@@ -664,8 +665,11 @@
 
   Returns the channel listened to, for future calls to `unlisten-chan!`."
   ([conn f]
-   {:pre [(fn? f)]}
-   (listen-chan! conn (-listen-chan f))))
+   ;; Decently large buffer before dropping, for JS consumers.
+   (listen! conn f 1024))
+  ([conn f n]
+   {:pre [(fn? f) (pos? n)]}
+   (listen-chan! conn (-listen-chan f n))))
 
 (defn unlisten-chan! [conn listener-sink]
   "Stop putting reports successfully transacted against the given connection onto the given channel."