Chore: export `closestIdx` from `StreamingDataFrame` (#45162)

* #41993: export closestIdx function

* #41993: formatting

* #41993: formatting v2

public/app/features/live/data/StreamingDataFrame.test.ts

@@ -1,8 +1,71 @@
-import { reduceField, ReducerID, getFieldDisplayName, DataFrame, FieldType, DataFrameJSON } from '@grafana/data';
+import { DataFrame, DataFrameJSON, FieldType, getFieldDisplayName, reduceField, ReducerID } from '@grafana/data';
 import { StreamingFrameAction, StreamingFrameOptions } from '@grafana/runtime';
-import { getStreamingFrameOptions, StreamingDataFrame } from './StreamingDataFrame';
+import { closestIdx, getStreamingFrameOptions, StreamingDataFrame } from './StreamingDataFrame';
 
 describe('Streaming JSON', () => {
+  describe('closestIdx', function () {
+    [
+      {
+        num: 10,
+        arr: [2, 3, 4, 5, 6],
+        expected: 4,
+        descr: 'bigger than all in array',
+      },
+      {
+        num: 10,
+        arr: [2, 3, 4, 5, 11, 12, 13],
+        expected: 4,
+        descr: 'bigger than some in array #1 - smaller difference to bigger number',
+      },
+      {
+        num: 10,
+        arr: [2, 3, 4, 5, 16, 17, 18],
+        expected: 3,
+        descr: 'bigger than some in array #2 - smaller difference to smaller number',
+      },
+      {
+        num: 10,
+        arr: [2, 3, 4, 9, 11, 12, 13],
+        expected: 3,
+        descr: 'bigger than some in array #3 - same difference between smaller and bigger number - favors smaller',
+      },
+      {
+        num: 10,
+        arr: [9, 10, 11, 12, 13, 14],
+        expected: 1,
+        descr: 'present in the array',
+      },
+      {
+        num: 10,
+        arr: [10, 11, 12, 13, 14],
+        expected: 0,
+        descr: 'present in the array on first position',
+      },
+      {
+        num: 10,
+        arr: [5, 6, 7, 8, 9, 10],
+        expected: 5,
+        descr: 'present in the array on last position',
+      },
+      {
+        num: 10,
+        arr: [11, 12, 13, 14, 15],
+        expected: 0,
+        descr: 'smaller than all in array',
+      },
+      {
+        num: 10,
+        arr: [],
+        expected: -1,
+        descr: 'empty array',
+      },
+    ].forEach(({ num, arr, expected, descr }) => {
+      it(descr, () => {
+        expect(closestIdx(num, arr)).toEqual(expected);
+      });
+    });
+  });
+
   describe('when called with a DataFrame', () => {
     const json: DataFrameJSON = {
       schema: {
@@ -506,7 +569,7 @@ describe('Streaming JSON', () => {
     expect(val).toEqual(200);
     expect(stream.length).toEqual(2);
 
-    const copy = ({ ...stream } as any) as DataFrame;
+    const copy = { ...stream } as any as DataFrame;
     expect(copy.length).toEqual(2);
   });
 

public/app/features/live/data/StreamingDataFrame.ts

@@ -1,23 +1,20 @@
 import {
+  ArrayVector,
   DataFrame,
+  DataFrameJSON,
+  decodeFieldValueEntities,
   Field,
   FieldDTO,
+  FieldSchema,
   FieldType,
+  guessFieldTypeFromValue,
   Labels,
+  parseLabels,
   QueryResultMeta,
-  DataFrameJSON,
-  decodeFieldValueEntities,
-  FieldSchema,
-  guessFieldTypeFromValue,
-  ArrayVector,
   toFilteredDataFrameDTO,
-  parseLabels,
 } from '@grafana/data';
 import { join } from '@grafana/data/src/transformations/transformers/joinDataFrames';
-import {
-  StreamingFrameAction,
-  StreamingFrameOptions,
-} from '@grafana/runtime/src/services/live';
+import { StreamingFrameAction, StreamingFrameOptions } from '@grafana/runtime/src/services/live';
 import { renderLegendFormat } from 'app/plugins/datasource/prometheus/legend';
 import { AlignedData } from 'uplot';
 
@@ -209,7 +206,7 @@ export class StreamingDataFrame implements DataFrame {
       const firstField = schema.fields[0];
       if (
         this.timeFieldIndex === 1 &&
-        firstField.type === FieldType.string && 
+        firstField.type === FieldType.string &&
         (firstField.name === 'labels' || firstField.name === 'Labels')
       ) {
         this.pushMode = PushMode.labels;
@@ -230,10 +227,10 @@ export class StreamingDataFrame implements DataFrame {
           const sf = niceSchemaFields[idx % len];
           f.config = sf.config ?? {};
           f.labels = sf.labels;
-        });        
+        });
         if (displayNameFormat) {
           this.fields.forEach((f) => {
-            const labels = {[PROM_STYLE_METRIC_LABEL]:f.name, ...f.labels};
+            const labels = { [PROM_STYLE_METRIC_LABEL]: f.name, ...f.labels };
             f.config.displayNameFromDS = renderLegendFormat(displayNameFormat, labels);
           });
         }
@@ -243,7 +240,7 @@ export class StreamingDataFrame implements DataFrame {
         this.fields = niceSchemaFields.map((f) => {
           const config = f.config ?? {};
           if (displayNameFormat) {
-            const labels = {[PROM_STYLE_METRIC_LABEL]:f.name, ...f.labels};
+            const labels = { [PROM_STYLE_METRIC_LABEL]: f.name, ...f.labels };
             config.displayNameFromDS = renderLegendFormat(displayNameFormat, labels);
           }
           return {
@@ -411,7 +408,7 @@ export class StreamingDataFrame implements DataFrame {
         if (i > 0) {
           f.labels = parsedLabels;
           if (displayNameFormat) {
-            const labels = {[PROM_STYLE_METRIC_LABEL]:f.name, ...parsedLabels};
+            const labels = { [PROM_STYLE_METRIC_LABEL]: f.name, ...parsedLabels };
             f.config.displayNameFromDS = renderLegendFormat(displayNameFormat, labels);
           }
         }
@@ -421,7 +418,7 @@ export class StreamingDataFrame implements DataFrame {
         let proto = this.schemaFields[i] as Field;
         const config = proto.config ?? {};
         if (displayNameFormat) {
-          const labels = {[PROM_STYLE_METRIC_LABEL]:proto.name, ...parsedLabels};
+          const labels = { [PROM_STYLE_METRIC_LABEL]: proto.name, ...parsedLabels };
           config.displayNameFromDS = renderLegendFormat(displayNameFormat, labels);
         }
         this.fields.push({
@@ -434,7 +431,7 @@ export class StreamingDataFrame implements DataFrame {
     }
 
     this.labels.add(label);
-  };
+  }
 
   getOptions = (): Readonly<StreamingFrameOptions> => this.options;
 }
@@ -473,7 +470,7 @@ export function transpose(vrecs: any[][]) {
 }
 
 // binary search for index of closest value
-function closestIdx(num: number, arr: number[], lo?: number, hi?: number) {
+export function closestIdx(num: number, arr: number[], lo?: number, hi?: number) {
   let mid;
   lo = lo || 0;
   hi = hi || arr.length - 1;