[v9.4.x] Transformations: Selectively apply transformation to queries (#62615)

Transformations: Selectively apply transformation to queries (#61735)

(cherry picked from commit bba80b6c7a)

Co-authored-by: Ryan McKinley <ryantxu@gmail.com>

packages/grafana-data/src/transformations/transformDataFrame.test.ts

@@ -3,10 +3,11 @@ import { FieldType } from '../types';
 import { mockTransformationsRegistry } from '../utils/tests/mockTransformationsRegistry';
 
 import { ReducerID } from './fieldReducer';
+import { FrameMatcherID } from './matchers/ids';
 import { transformDataFrame } from './transformDataFrame';
 import { filterFieldsByNameTransformer } from './transformers/filterByName';
 import { DataTransformerID } from './transformers/ids';
-import { reduceTransformer } from './transformers/reduce';
+import { reduceTransformer, ReduceTransformerMode } from './transformers/reduce';
 
 const seriesAWithSingleField = toDataFrame({
   name: 'A',
@@ -73,4 +74,44 @@ describe('transformDataFrame', () => {
       expect(processed[0].fields[0].values.get(0)).toEqual('temperature');
     });
   });
+
+  it('Support filtering', async () => {
+    const frameA = toDataFrame({
+      refId: 'A',
+      fields: [{ name: 'value', type: FieldType.number, values: [5, 6] }],
+    });
+    const frameB = toDataFrame({
+      refId: 'B',
+      fields: [{ name: 'value', type: FieldType.number, values: [7, 8] }],
+    });
+
+    const cfg = [
+      {
+        id: DataTransformerID.reduce,
+        filter: {
+          id: FrameMatcherID.byRefId,
+          options: 'A', // Only apply to A
+        },
+        options: {
+          reducers: [ReducerID.first],
+          mode: ReduceTransformerMode.ReduceFields,
+        },
+      },
+    ];
+
+    // Only apply A
+    await expect(transformDataFrame(cfg, [frameA, frameB])).toEmitValuesWith((received) => {
+      const processed = received[0].map((v) => v.fields[0].values.toArray());
+      expect(processed).toBeTruthy();
+      expect(processed).toMatchObject([[5], [7, 8]]);
+    });
+
+    // Only apply to B
+    cfg[0].filter.options = 'B';
+    await expect(transformDataFrame(cfg, [frameA, frameB])).toEmitValuesWith((received) => {
+      const processed = received[0].map((v) => v.fields[0].values.toArray());
+      expect(processed).toBeTruthy();
+      expect(processed).toMatchObject([[5, 6], [7]]);
+    });
+  });
 });