Visualize: Bad request when working with histogram aggregation (#77684)

* Visualize: Bad request when working with histogram aggregation

Closes: #77023

* ✏️ Add some more fix context

* ✅ Add test

Co-authored-by: dej611 <[email protected]>
Co-authored-by: Elastic Machine <[email protected]>

Author: 3 people

src/plugins/data/common/search/aggs/buckets/lib/histogram_calculate_interval.test.ts

@@ -139,6 +139,19 @@ describe('calculateHistogramInterval', () => {
           })
         ).toEqual(0.02);
       });
+
+      test('should correctly fallback to the default value for empty string', () => {
+        expect(
+          calculateHistogramInterval({
+            ...params,
+            maxBucketsUserInput: '',
+            values: {
+              min: 0.1,
+              max: 0.9,
+            },
+          })
+        ).toBe(0.01);
+      });
     });
   });
 });

src/plugins/data/common/search/aggs/buckets/lib/histogram_calculate_interval.ts

@@ -27,7 +27,7 @@ interface IntervalValuesRange {
 export interface CalculateHistogramIntervalParams {
   interval: string;
   maxBucketsUiSettings: number;
-  maxBucketsUserInput?: number;
+  maxBucketsUserInput?: number | '';
   intervalBase?: number;
   values?: IntervalValuesRange;
 }
@@ -77,12 +77,7 @@ const calculateForGivenInterval = (
      - The lower power of 10, times 2
      - The lower power of 10, times 5
  **/
-const calculateAutoInterval = (
-  diff: number,
-  maxBucketsUiSettings: CalculateHistogramIntervalParams['maxBucketsUiSettings'],
-  maxBucketsUserInput: CalculateHistogramIntervalParams['maxBucketsUserInput']
-) => {
-  const maxBars = Math.min(maxBucketsUiSettings, maxBucketsUserInput ?? maxBucketsUiSettings);
+const calculateAutoInterval = (diff: number, maxBars: number) => {
   const exactInterval = diff / maxBars;
 
   const lowerPower = Math.pow(10, Math.floor(Math.log10(exactInterval)));
@@ -122,7 +117,11 @@ export const calculateHistogramInterval = ({
 
     if (diff) {
       calculatedInterval = isAuto
-        ? calculateAutoInterval(diff, maxBucketsUiSettings, maxBucketsUserInput)
+        ? calculateAutoInterval(
+            diff,
+            // Mind maxBucketsUserInput can be an empty string, hence we need to ensure it here
+            Math.min(maxBucketsUiSettings, maxBucketsUserInput || maxBucketsUiSettings)
+          )
         : calculateForGivenInterval(diff, calculatedInterval, maxBucketsUiSettings);
     }
   }