From bcfe80fbdce44ab56b0d7f8fbfe7920bf354fa81 Mon Sep 17 00:00:00 2001
From: Victor Woeltjen <victor.woeltjen@nasa.gov>
Date: Wed, 24 Jun 2015 12:54:49 -0700
Subject: [PATCH] [Plot] Handle changes to telemetry objects

Handle changes to the set of visible telemetry objects
in a plot; addresses WTD-619, which is related to WTD-1329.
---
 .../features/plot/src/elements/PlotUpdater.js | 28 +++++++++----------
 .../telemetry/src/TelemetrySubscription.js    | 10 ++++---
 2 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/platform/features/plot/src/elements/PlotUpdater.js b/platform/features/plot/src/elements/PlotUpdater.js
index df7eef9abc..e31641f7c7 100644
--- a/platform/features/plot/src/elements/PlotUpdater.js
+++ b/platform/features/plot/src/elements/PlotUpdater.js
@@ -50,6 +50,7 @@ define(
                 origin = [0, 0],
                 domainExtrema,
                 rangeExtrema,
+                buffers = {},
                 bufferArray = [],
                 domainOffset;
 
@@ -61,11 +62,10 @@ define(
             // Check if this set of ids matches the current set of ids
             // (used to detect if line preparation can be skipped)
             function idsMatch(nextIds) {
-                return nextIds.map(function (id, index) {
-                    return ids[index] === id;
-                }).reduce(function (a, b) {
-                    return a && b;
-                }, true);
+                return ids.length === nextIds.length &&
+                    nextIds.every(function (id, index) {
+                        return ids[index] === id;
+                    });
             }
 
             // Prepare plot lines for this group of telemetry objects
@@ -74,7 +74,7 @@ define(
                     next = {};
 
                 // Detect if we already have everything we need prepared
-                if (ids.length === nextIds.length && idsMatch(nextIds)) {
+                if (idsMatch(nextIds)) {
                     // Nothing to prepare, move on
                     return;
                 }
@@ -88,13 +88,13 @@ define(
 
                     // Create buffers for these objects
                     bufferArray = ids.map(function (id) {
-                        var buffer = new PlotLineBuffer(
-                                domainOffset,
-                                INITIAL_SIZE,
-                                maxPoints
-                            );
-                        next[id] = lines[id] || new PlotLine(buffer);
-                        return buffer;
+                        buffers[id] = buffers[id] || new PlotLineBuffer(
+                            domainOffset,
+                            INITIAL_SIZE,
+                            maxPoints
+                        );
+                        next[id] = lines[id] || new PlotLine(buffers[id]);
+                        return buffers[id];
                     });
                 }
 
@@ -290,4 +290,4 @@ define(
         return PlotUpdater;
 
     }
-);
\ No newline at end of file
+);
diff --git a/platform/telemetry/src/TelemetrySubscription.js b/platform/telemetry/src/TelemetrySubscription.js
index f8481eb085..69fd957ac2 100644
--- a/platform/telemetry/src/TelemetrySubscription.js
+++ b/platform/telemetry/src/TelemetrySubscription.js
@@ -147,7 +147,8 @@ define(
                 telemetryObjects = objects;
                 metadatas = objects.map(lookupMetadata);
                 // Fire callback, as this will be the first time that
-                // telemetry objects are available
+                // telemetry objects are available, or these objects
+                // will have changed.
                 if (callback) {
                     callback();
                 }
@@ -176,9 +177,10 @@ define(
             }
 
             function idsMatch(ids) {
-                return ids.every(function (id, index) {
-                    return telemetryObjects[index].getId() === id;
-                });
+                return ids.length === telemetryObjects.length &&
+                    ids.every(function (id, index) {
+                        return telemetryObjects[index].getId() === id;
+                    });
             }
 
             function modelChange(model) {