From a3695b8da2cf0b197e142b570aabcab5e06703e3 Mon Sep 17 00:00:00 2001
From: Oliver Hine <git@oliy.co.uk>
Date: Tue, 25 Aug 2020 16:39:03 +0100
Subject: [PATCH] Improving docs, guarding against pending-operations being
 nilled #93

---
 re-frame/README.md                 | 21 +++++++++++----------
 re-frame/src/martian/re_frame.cljs |  4 ++--
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/re-frame/README.md b/re-frame/README.md
index 607fec7..6555361 100644
--- a/re-frame/README.md
+++ b/re-frame/README.md
@@ -12,6 +12,8 @@ that martian can bring:
 ```clj
 (require '[martian.re-frame :as martian])
 (require '[re-frame.core :as re-frame])
+(require '[cljs.core.async :refer [<!]])
+(require-macros '[cljs.core.async.macros :refer [go]])
 
 (def interceptors [re-frame/trim-v])
 
@@ -27,14 +29,13 @@ that martian can bring:
  (fn [db [response-or-error operation-id params]]
    (update db :errors conj [operation-id response-or-error])))
 
-(martian/init "http://pedestal-api.herokuapp.com/swagger.json")
-
-(re-frame/dispatch [::martian/request             ;; event for performing an http request
-                    :create-pet               ;; the route name to call
-                    {:name "Doggy McDogFace"  ;; data to send to the endpoint
-                     :type "Dog"
-                     :age 3}
-                    ::create-pet-success      ;; event to dispatch on success
-                    ::http-failure            ;; event to dispatch on failure
-                    ])
+(go (<! (martian/init "http://pedestal-api.herokuapp.com/swagger.json"))
+    (re-frame/dispatch [::martian/request             ;; event for performing an http request
+                        :create-pet               ;; the route name to call
+                        {:name "Doggy McDogFace"  ;; data to send to the endpoint
+                         :type "Dog"
+                         :age 3}
+                        [::create-pet-success]    ;; event to dispatch on success
+                        [::http-failure]          ;; event to dispatch on failure
+                       ]))
 ```
diff --git a/re-frame/src/martian/re_frame.cljs b/re-frame/src/martian/re_frame.cljs
index 7c1e75a..0524c5d 100644
--- a/re-frame/src/martian/re_frame.cljs
+++ b/re-frame/src/martian/re_frame.cljs
@@ -36,13 +36,13 @@
 (re-frame/reg-event-db
  ::on-complete
  (fn [db [_ req]]
-   (update-in db [::martian :pending] disj req)))
+   (update-in db [::martian :pending] (fnil disj #{}) req)))
 
 (defn- do-request [{:keys [db]} [_ operation-id params on-success on-failure]]
   (let [request-key [operation-id params on-success on-failure]]
     (if (contains? (get-in db [::martian :pending]) request-key)
       {:db db}
-      {:db (update-in db [::martian :pending] conj request-key)
+      {:db (update-in db [::martian :pending] (fnil conj #{}) request-key)
        ::request [(instance db) operation-id params on-success on-failure]})))
 
 ;; deprecated, use ::request instead