Transformations: Handle undefined values when calculating mean and total in add field from calculations (#78645)

* Transformations: Handle undefined values when calculating mean and total in add field from calculations

* fix typo

* change to != and add tests

packages/grafana-data/src/transformations/transformers/calculateField.test.ts

@@ -597,6 +597,32 @@ describe('calculateField transformer w/ timeseries', () => {
       expect(data.fields[1].values[2]).toEqual(2);
     });
   });
+  it('calculates cumulative total with undefined values', async () => {
+    const cfg = {
+      id: DataTransformerID.calculateField,
+      options: {
+        mode: CalculateFieldMode.CumulativeFunctions,
+        cumulative: {
+          field: 'x',
+          reducer: ReducerID.sum,
+        },
+      },
+    };
+
+    const series = toDataFrame({
+      fields: [{ name: 'x', type: FieldType.number, values: [1, undefined, 2, 3] }],
+    });
+
+    await expect(transformDataFrame([cfg], [series])).toEmitValuesWith((received) => {
+      const data = received[0][0];
+
+      expect(data.fields.length).toEqual(2);
+      expect(data.fields[1].values[0]).toEqual(1);
+      expect(data.fields[1].values[1]).toEqual(1);
+      expect(data.fields[1].values[2]).toEqual(3);
+      expect(data.fields[1].values[3]).toEqual(6);
+    });
+  });
 
   it('calculates cumulative total with nulls', async () => {
     const cfg = {
@@ -743,6 +769,36 @@ describe('calculateField transformer w/ timeseries', () => {
     });
   });
 
+  it('calculates centered moving average with undefined values', async () => {
+    const cfg = {
+      id: DataTransformerID.calculateField,
+      options: {
+        mode: CalculateFieldMode.WindowFunctions,
+        window: {
+          windowAlignment: WindowAlignment.Centered,
+          field: 'x',
+          windowSize: 0.75,
+          windowSizeMode: WindowSizeMode.Percentage,
+          reducer: ReducerID.mean,
+        },
+      },
+    };
+
+    const series = toDataFrame({
+      fields: [{ name: 'x', type: FieldType.number, values: [1, undefined, 2, 7] }],
+    });
+
+    await expect(transformDataFrame([cfg], [series])).toEmitValuesWith((received) => {
+      const data = received[0][0];
+
+      expect(data.fields.length).toEqual(2);
+      expect(data.fields[1].values[0]).toEqual(1);
+      expect(data.fields[1].values[1]).toEqual(1.5);
+      expect(data.fields[1].values[2]).toEqual(4.5);
+      expect(data.fields[1].values[3]).toEqual(4.5);
+    });
+  });
+
   it('calculates centered moving average with nulls', async () => {
     const cfg = {
       id: DataTransformerID.calculateField,

packages/grafana-data/src/transformations/transformers/calculateField.ts

@@ -277,7 +277,7 @@ function getTrailingWindowValues(frame: DataFrame, reducer: ReducerID, selectedF
   for (let i = 0; i < frame.length; i++) {
     if (reducer === ReducerID.mean) {
       const currentValue = selectedField.values[i];
-      if (currentValue !== null) {
+      if (currentValue !== null && currentValue !== undefined) {
         count++;
         sum += currentValue;
 
@@ -315,7 +315,7 @@ function getCenteredWindowValues(frame: DataFrame, reducer: ReducerID, selectedF
       if (i === 0) {
         // We're at the start and need to prime the leading part of the window
         for (let x = 0; x < leadingPartOfWindow + 1 && x < selectedField.values.length; x++) {
-          if (selectedField.values[x] !== null) {
+          if (selectedField.values[x] != null) {
             sum += selectedField.values[x];
             count++;
           }
@@ -323,14 +323,14 @@ function getCenteredWindowValues(frame: DataFrame, reducer: ReducerID, selectedF
       } else {
         if (last < selectedField.values.length) {
           // Last is inside the data and should be added.
-          if (selectedField.values[last] !== null) {
+          if (selectedField.values[last] != null) {
             sum += selectedField.values[last];
             count++;
           }
         }
         if (first > 0) {
           // Remove values that have fallen outside of the window, if the start of the window isn't outside of the data.
-          if (selectedField.values[first - 1] !== null) {
+          if (selectedField.values[first - 1] != null) {
             sum -= selectedField.values[first - 1];
             count--;
           }
@@ -363,7 +363,7 @@ function calculateVariance(vals: number[]): number {
   let nonNullCount = 0;
   for (let i = 0; i < vals.length; i++) {
     const currentValue = vals[i];
-    if (currentValue !== null) {
+    if (currentValue != null) {
       nonNullCount++;
       let _oldMean = runningMean;
       runningMean += (currentValue - _oldMean) / nonNullCount;
@@ -417,7 +417,7 @@ function getCumulativeCreator(options: CumulativeOptions, allFrames: DataFrame[]
 
     let total = 0;
     for (let i = 0; i < frame.length; i++) {
-      total += selectedField.values[i];
+      total += selectedField.values[i] ?? 0;
       if (options.reducer === ReducerID.sum) {
         vals.push(total);
       } else if (options.reducer === ReducerID.mean) {