Bug fixes for plots (#3019) (#3069)

* prevent plots from breaking when more than one NaN is received.

* fix y axis label issue

* dont emit a viewport change event when marquee doesnt happen

src/plugins/plot/src/configuration/PlotSeries.js

@@ -324,7 +324,15 @@ define([
          *                  a point to the end without dupe checking.
          */
         add: function (point, appendOnly) {
-            var insertIndex = this.data.length;
+            var insertIndex = this.data.length,
+                currentYVal = this.getYVal(point),
+                lastYVal = this.getYVal(this.data[insertIndex - 1]);
+
+            if (this.isValueInvalid(currentYVal) && this.isValueInvalid(lastYVal)) {
+                console.warn('[Plot] Invalid Y Values detected');
+                return;
+            }
+
             if (!appendOnly) {
                 insertIndex = this.sortedIndex(point);
                 if (this.getXVal(this.data[insertIndex]) === this.getXVal(point)) {
@@ -334,11 +342,21 @@ define([
                     return;
                 }
             }
+
             this.updateStats(point);
             point.mctLimitState = this.evaluate(point);
             this.data.splice(insertIndex, 0, point);
             this.emit('add', point, insertIndex, this);
         },
+
+        /**
+         *
+         * @private
+         */
+        isValueInvalid: function (val) {
+            return Number.isNaN(val) || val === undefined;
+        },
+
         /**
          * Remove a point from the data array and notify listeners.
          * @private

src/plugins/plot/src/configuration/YAxisModel.js

@@ -182,21 +182,6 @@ define([
             this.set('format', yFormat.format.bind(yFormat));
             this.set('values', yMetadata.values);
             if (!label) {
-                var labelUnits = series.map(function (s) {
-                    return s.metadata.value(s.get('yKey')).units;
-                }).reduce(function (a, b) {
-                    if (a === undefined) {
-                        return b;
-                    }
-                    if (a === b) {
-                        return a;
-                    }
-                    return '';
-                }, undefined);
-                if (labelUnits) {
-                    this.set('label', labelUnits);
-                    return;
-                }
                 var labelName = series.map(function (s) {
                     return s.metadata.value(s.get('yKey')).name;
                 }).reduce(function (a, b) {
@@ -208,7 +193,28 @@ define([
                     }
                     return '';
                 }, undefined);
-                this.set('label', labelName);
+
+                if (labelName) {
+                    this.set('label', labelName);
+                    return;
+                }
+
+                var labelUnits = series.map(function (s) {
+                    return s.metadata.value(s.get('yKey')).units;
+                }).reduce(function (a, b) {
+                    if (a === undefined) {
+                        return b;
+                    }
+                    if (a === b) {
+                        return a;
+                    }
+                    return '';
+                }, undefined);
+
+                if (labelUnits) {
+                    this.set('label', labelUnits);
+                    return;
+                }
             }
         },
         defaults: function (options) {