From 80c818c7629f468c90cae07908c7e2a95ae81878 Mon Sep 17 00:00:00 2001
From: Joel Mason <jobba1@hotmail.com>
Date: Wed, 2 Nov 2016 07:38:10 +1100
Subject: [PATCH] Fixes use with Interact in IJulia on page refresh

See https://github.com/JuliaLang/Interact.jl/issues/115 for more context
---
 src/PlotlyJS.jl        |  2 +-
 src/displays/ijulia.jl | 10 +++++++---
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/PlotlyJS.jl b/src/PlotlyJS.jl
index 4247d691..9837dc29 100644
--- a/src/PlotlyJS.jl
+++ b/src/PlotlyJS.jl
@@ -121,7 +121,7 @@ function __init__()
         end
 
         # set up the comms we will use to send js messages to be executed
-        global const _ijulia_eval_comm = Comm(:plotlyjs_eval)
+        global const _ijulia_eval_comm = Ref(Comm(:plotlyjs_eval))
         global const _ijulia_return_comms = ObjectIdDict()
 
         @eval begin
diff --git a/src/displays/ijulia.jl b/src/displays/ijulia.jl
index 819b9bd1..2ae18d41 100644
--- a/src/displays/ijulia.jl
+++ b/src/displays/ijulia.jl
@@ -10,7 +10,10 @@ end
 
 typealias JupyterPlot SyncPlot{JupyterDisplay}
 
-JupyterDisplay(p::Plot) = JupyterDisplay(p.divid, false, Condition())
+JupyterDisplay(p::Plot) = begin
+    _ijulia_eval_comm[] = Comm(:plotlyjs_eval)
+    JupyterDisplay(p.divid, false, Condition())
+end
 JupyterPlot(p::Plot) = JupyterPlot(p, JupyterDisplay(p))
 
 fork(jp::JupyterPlot) = JupyterPlot(fork(jp.plot))
@@ -71,8 +74,9 @@ end
 # Helper functions #
 # ---------------- #
 
-_call_js(jd::JupyterDisplay, code) =
-    send_comm(_ijulia_eval_comm, Dict("code" => code))
+_call_js(jd::JupyterDisplay, code) = begin
+    send_comm(_ijulia_eval_comm[], Dict("code" => code))
+end
 
 ## API Methods for JupyterDisplay
 _the_div_js(jd::JupyterDisplay) = "document.getElementById('$(jd.divid)')"