[Fixed Position] Do not just show range values, be more flexible to other telemetry types. Fixes #1740

platform/features/layout/src/FixedController.js

@@ -360,22 +360,47 @@ define(
          */
         FixedController.prototype.updateView = function (telemetryObject, datum) {
             var metadata = this.openmct.telemetry.getMetadata(telemetryObject);
-            var rangeMetadata = metadata.valuesForHints(['range'])[0];
+            var telemetryKeyToDisplay = this.chooseTelemetryKeyToDisplay(metadata);
-            var rangeKey = rangeMetadata.source || rangeMetadata.key;
+            var formattedTelemetryValue = this.getFormattedTelemetryValueForKey(telemetryKeyToDisplay, datum, metadata);
-            var valueMetadata = metadata.value(rangeKey);
             var limitEvaluator = this.openmct.telemetry.limitEvaluator(telemetryObject);
-            var formatter = this.openmct.telemetry.getValueFormatter(valueMetadata);
+            var alarm = limitEvaluator && limitEvaluator.evaluate(datum, telemetryKeyToDisplay);
-            var value = datum[valueMetadata.key];
-            var alarm = limitEvaluator && limitEvaluator.evaluate(datum, rangeKey);
 
             this.setDisplayedValue(
                 telemetryObject,
-                formatter.format(value),
+                formattedTelemetryValue,
                 alarm && alarm.cssClass
             );
             this.digest();
         };
 
+        /**
+         * @private
+         */
+        FixedController.prototype.getFormattedTelemetryValueForKey = function (telemetryKeyToDisplay, datum, metadata) {
+            var valueMetadata = metadata.value(telemetryKeyToDisplay);
+            var formatter = this.openmct.telemetry.getValueFormatter(valueMetadata);
+
+            return formatter.format(datum[valueMetadata.key]);
+        };
+
+        /**
+         * @private
+         */
+        FixedController.prototype.chooseTelemetryKeyToDisplay = function (metadata) {
+            // If there is a range value, show that preferentially
+            var telemetryKeyToDisplay = metadata.valuesForHints(['range'])[0];
+
+            // If no range is defined, default to the highest priority non time-domain data.
+            if (telemetryKeyToDisplay === undefined) {
+                var valuesOrderedByPriority = metadata.values();
+                telemetryKeyToDisplay = valuesOrderedByPriority.filter(function (valueMetadata) {
+                    return !(valueMetadata.hints.domain);
+                })[0];
+            }
+
+            return telemetryKeyToDisplay.source;
+        };
+
         /**
          * Request the last historical data point for the given domain objects
          * @param {object[]} objects
@@ -388,7 +413,9 @@ define(
             objects.forEach(function (object) {
                 self.openmct.telemetry.request(object, {start: bounds.start, end: bounds.end, size: 1})
                     .then(function (data) {
-                        self.updateView(object, data[data.length - 1]);
+                        if (data.length > 0) {
+                            self.updateView(object, data[data.length - 1]);
+                        }
                     });
             });
             return objects;

platform/features/layout/test/FixedControllerSpec.js

@@ -178,7 +178,6 @@ define(
                     Promise.resolve(mockChildren)
                 );
 
-
                 mockScope.model = testModel;
                 mockScope.configuration = testConfiguration;
                 mockScope.selection = jasmine.createSpyObj(
@@ -194,7 +193,8 @@ define(
 
                 mockMetadata = jasmine.createSpyObj('mockMetadata', [
                     'valuesForHints',
-                    'value'
+                    'value',
+                    'values'
                 ]);
                 mockMetadata.value.andReturn({
                     key: 'value'
@@ -653,6 +653,39 @@ define(
                     });
                 });
 
+                it("selects an range value to display, if available", function () {
+                    mockMetadata.valuesForHints.andReturn([
+                        {
+                            key: 'range',
+                            source: 'range'
+                        }
+                    ]);
+                    var key = controller.chooseTelemetryKeyToDisplay(mockMetadata);
+                    expect(key).toEqual('range');
+                });
+
+                it("selects the first non-domain value to display, if no range available", function () {
+                    mockMetadata.valuesForHints.andReturn([]);
+                    mockMetadata.values.andReturn([
+                        {
+                            key: 'domain',
+                            source: 'domain',
+                            hints: {
+                                domain: 1
+                            }
+                        },
+                        {
+                            key: 'image',
+                            source: 'image',
+                            hints: {
+                                image: 1
+                            }
+                        }
+                    ]);
+                    var key = controller.chooseTelemetryKeyToDisplay(mockMetadata);
+                    expect(key).toEqual('image');
+                });
+
                 it("reflects limit status", function () {
                     mockLimitEvaluator.evaluate.andReturn({cssClass: "alarm-a"});
                     controller.updateView(mockTelemetryObject, [{