From beca2881dfe0eafbd2f0ca70a999e436a3b738f6 Mon Sep 17 00:00:00 2001
From: Daniel Compton <desk@danielcompton.net>
Date: Tue, 30 Jan 2018 10:49:26 +1300
Subject: [PATCH] Distinguish between subscriptions returning nil and not run

---
 CHANGELOG.md                           |  1 +
 src/day8/re_frame/trace/subs.cljs      | 35 ++++++++++++++------------
 src/day8/re_frame/trace/view/subs.cljs | 10 +++++---
 3 files changed, 26 insertions(+), 20 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b00b356..19dc72b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -25,6 +25,7 @@ This version requires re-frame 0.10.4 to make use of the newly added Event panel
 * All app-db and subscription path expansions are now independent of each other [#134](https://github.com/Day8/re-frame-trace/issues/134).
 * Layer 2/3 calculations are more accurate now. We now use the last seen layer level when a subscription runs, to inform it's layer level if it was created or destroyed.
 * View namespaces that are ignored are no longer shown when showing traces for all epochs.
+* Distinguish between subscriptions that return `nil` values and those that haven't run yet.
 
 
 
diff --git a/src/day8/re_frame/trace/subs.cljs b/src/day8/re_frame/trace/subs.cljs
index a806c46..b1607a8 100644
--- a/src/day8/re_frame/trace/subs.cljs
+++ b/src/day8/re_frame/trace/subs.cljs
@@ -391,22 +391,25 @@
   :<- [:app-db/reagent-id]
   :<- [:subs/subscription-info]
   (fn [[traces app-db-id sub-info]]
-    (let [raw           (map (fn [trace] (let [pod-type  (sub-op-type->type trace)
-                                               path-data (get-in trace [:tags :query-v])
-                                               ;; TODO: detect layer 2/3 for sub/create and sub/destroy
-                                               ;; This information needs to be accumulated.
-                                               layer     (if (some #(= app-db-id %) (get-in trace [:tags :input-signals]))
-                                                           2
-                                                           3)]
-                                           {:id        (str pod-type (get-in trace [:tags :reaction]))
-                                            :type      pod-type
-                                            :layer     (get-in sub-info [(:operation trace) :layer])
-                                            :path-data path-data
-                                            :path      (pr-str path-data)
-                                            :value     (get-in trace [:tags :value])
-
-                                            ;; TODO: Get not run subscriptions
-                                            }))
+    (let [raw           (map (fn [trace]
+                               (let [pod-type  (sub-op-type->type trace)
+                                     path-data (get-in trace [:tags :query-v])
+                                     ;; TODO: detect layer 2/3 for sub/create and sub/destroy
+                                     ;; This information needs to be accumulated.
+                                     layer     (if (some #(= app-db-id %) (get-in trace [:tags :input-signals]))
+                                                 2
+                                                 3)
+                                     sub
+                                     (-> {:id        (str pod-type (get-in trace [:tags :reaction]))
+                                          :type      pod-type
+                                          :layer     (get-in sub-info [(:operation trace) :layer])
+                                          :path-data path-data
+                                          :path      (pr-str path-data)
+                                          ;; TODO: Get not run subscriptions
+                                          })]
+                                 (if (contains? (:tags trace) :value)
+                                   (assoc sub :value (get-in trace [:tags :value]))
+                                   sub)))
                              traces)
           re-run        (->> raw
                              (filter #(= :re-run (:type %)))
diff --git a/src/day8/re_frame/trace/view/subs.cljs b/src/day8/re_frame/trace/view/subs.cljs
index a6cbcc1..509ca48 100644
--- a/src/day8/re_frame/trace/view/subs.cljs
+++ b/src/day8/re_frame/trace/view/subs.cljs
@@ -169,10 +169,12 @@
                                 :style {:margin     (css-join pod-padding pod-padding "0px" pod-padding)
                                         :overflow-x "auto"
                                         :overflow-y "hidden"}
-                                :children [[components/simple-render
-                                            (:value pod-info)
-                                            ["sub-path" path]
-                                            ]]])]
+                                :children [(if (contains? pod-info :value)
+                                             [components/simple-render
+                                              (:value pod-info)
+                                              ["sub-path" path]]
+                                             [rc/label :style {:font-style "italic"} :label "Subscription not run, so no value produced."]
+                                             )]])]
                             [animated/component
                              (animated/v-box-options {:enter-animation "accordionVertical"
                                                       :leave-animation "accordionVertical"